Answer:
D. 5x^2(x^2+2x+3)
Step-by-step explanation:
Factorization involves the algebraic expression in such a manner that there are two groups with a common element between them.
As such, given 5x^4+10x^3+15x^2
The common factor among all 3 individual elements of the  expression is 5x^2. taking this out of each element, the factors left are as shown below.
5x^4+10x^3+15x^2 = 5x^2(x^2 + 2x + 3)
D. 5x^2(x^2+2x+3) is the right option.
