x² + 10x – 18
Find factors of x² and -18 that will give you 10x when added
x² + 10x – 18
this is a prime, because there are no factors of -18 (-9 and 2 with negative interchangeably, and -6 and 3, with negative interchangeably) that will give you 10.
Therefore, you're answer is D. prime
hope this helps