a. Is the statement "Every elementary row operation is reversible" true or false? Explain. A. True, because interchanging can be reversed by scaling, and scaling can be reversed by replacement. B. False, because only scaling and interchanging are reversible row operations. C. True, because replacement, interchanging, and scaling are all reversible. D. False, because only interchanging is a reversible row operation.

Answer: C. True, because replacement, interchanging, and scaling are all reversible.

Step-by-step explanation:

Elementary operations in a matrix are defined as:

Operations in arithmetic (such as add, subtract, multiply, divide). They are of two kinds : Elementary row operations and elementary column operations.

Every elementary row operation is reversible.

If we add row to the another row then we can reverse it by subtracting the first row from the other on the next step If we interchange a row by another then we can again interchange it on the next step. If we we multiply a constant on a row, we can reverse it by multiplying the inverse of the constant to the row on the next step.

Therefore, the correct answer is C. True, because replacement, interchanging, and scaling are all reversible.