Explanation:

- Statement 1: If the product $AB$ is a null matrix (all elements are zero), it does not necessarily mean that one of the matrices $A$ or $B$ must be a null matrix. Both matrices could be non-zero. This typically happens in cases where neither $A$ nor $B$ are invertible. So, statement 1 is incorrect.

- Statement 2: If $AB$ results in an identity matrix, then both $A$ and $B$ are invertible, and $B$ is the inverse of $A$. In this special case, due to the properties of inverses, $BA$ will equal $AB$. Hence, statement 2 is correct.

- Options: Based on the analysis:

- Option 1: Incorrect as statement 1 is not valid.

- Option 2: Correct because only statement 2 is true.

- Option 3: Incorrect as statement 1 is false.

- Option 4: Incorrect because statement 2 is true.

Correct Answer: Option 2 - 2 only