Answer:
A. a × 1
Explanation:
The identity property of multiplication simply states that a number equals itself when multiplied by 1.
a × 1 is the identity property of multiplication.
(a + b) + 3 = a + (3 + b) is associative property.
a(b + c) = ab + ac is expansion.
a + a + a = 3 x a is factoring of like terms.