In Go, the 't.Parallel()' method in the 'testing' package is used to allow parallel execution of tests. When a test function calls 't.Parallel()', it informs the testing framework that this test can be run in parallel with other tests. This can help in speeding up the test execution time, especially when dealing with I/O-bound or CPU-bound tests. It's essential to ensure that the test functions are safe for parallel execution to avoid race conditions or other concurrency issues.

In Go, anonymous functions are declared using the func keyword followed by an optional parameter list and return type. Thus, the correct option is 'anonymous'.

The select statement in Go is used to wait on multiple channel operations simultaneously. It allows a goroutine to proceed as soon as one of the channels is ready to communicate, enabling efficient communication and synchronization between goroutines. This is particularly useful in scenarios where multiple channels are involved, and the program needs to react to whichever channel becomes ready first.

The "rollback" operation in a transaction signifies undoing or reverting the changes made by the transaction, restoring the database to its state before the transaction started. It is typically used to handle errors or ensure data integrity by discarding incomplete or erroneous transactions.

In Go, the keyword used to handle errors returned by functions is 'err'. When a function can return an error, it typically uses this keyword as a convention for error handling.

The '-race' flag, when used with the 'go test' command in Go, enables race condition detection during the execution of concurrent Go programs. Race conditions occur when two or more goroutines access shared data concurrently, and at least one of the accesses is a write operation. This flag instruments the Go program's code to track accesses to shared variables and detects potential data races during runtime. It helps in identifying and fixing concurrency bugs early in the development cycle, ensuring the correctness and stability of concurrent Go programs.

ORM libraries in Go utilize struct tags to define relationships between different database tables. Struct tags are annotations added to struct fields that provide metadata used by ORM libraries to map Go objects to database tables and define relationships.

In Go, JSON decoding errors are typically handled by checking the error returned by the json.Unmarshal function. This function returns an error if the JSON decoding fails, allowing developers to handle it gracefully. Ignoring errors or using panic() is generally discouraged as it can lead to unexpected behavior and make the code harder to debug. Handling errors with a custom error message provides better insight into the specific issue encountered during JSON decoding.

Anonymous functions in Go are commonly used to implement concurrency patterns like goroutines. They allow for the concurrent execution of tasks, enhancing the performance of Go programs.

The correct keyword to create a goroutine in Go is 'go'. When 'go' keyword is used in front of a function call, it instructs Go runtime to execute that function concurrently as a goroutine.