Answer:
C. 45 × 45
Explanation:
You want to know the expanded form of 45 squared.
Square
A square is signified by an exponent of 2:
45 squared = 45²
The exponent tells you the number of times the base appears as a factor in the product:
45² = 45 × 45 . . . . . . . 45 is a factor 2 times in the product
__
Additional comment
The value "45 squared" is the area of a square of side length 45.
The value "45 cubed" is the volume of a cube of side length 45.