According to the BSA Framework, which of the following represents a function?

$1.$

According to the BSA Framework, a function is a fundamental software security activity at the highest level.

$2.$

According to the BSA Framework, a function represents additional information such as examples of how organizations achieve security outcomes.

$3.$

According to the BSA Framework, a function represents a distinct, unitary concept that express identified software security best practices

$4.$

According to the BSA Framework, a function represents a specific, verifiable outcome of a secure software activity.