If n and k are integers whose product is 400, which of the following statements must be true?
Choose the most appropriate option:
A) n + k > 0	B) n is not equal to k.	C) Either n or k is a multiple of 10.	D) If n is even, then k is odd.	E) If n is odd, then k is even.
For the product of two integers to be even at least one integer must be even.   A. n+k&gt;0 --&gt; not necessarily true: nk=(−20)∗(−20)=400   B. n does not equal k --&gt; not necessarily true: nk=20∗20=400   C. Either n or k is a multiple of 10 --&gt; not necessarily true: nk=16∗25=400   D. If n is even, then k is odd --&gt; not necessarily true, nn can be even and kk be even too --&gt; nk=20∗20=400   E. If n is odd, then k is even --&gt; this must be true, if one of the factors is odd (nn) the second one (kk) must be even for their product to be even.   Answer: If n is odd, then k is even..
<result>E</result>
If n and k are integers whose product is 400, which of the following statements must be true?