Question:

Choose the correct answer

Every identity matrix is a scalar matrix

Every scalar matrix is an identity matrix

Every diagonal matrix is an identity matrix

A square matrix whose each element is 1 is an identity matrix

Step-by-Step Solution

Key Concept: An identity matrix is a specific type of scalar matrix where the diagonal elements are all equal to the constant value of one.

We know that every identity matrix is a scalar matrix.

Correct Answer: A