If j and k are integers and j^2 / k is odd, which of the following must be true ?

Given: \(j\) and \(k\) are integers and \(\frac{j^2}{k}=odd\) --> \(j^2=k*odd\)

(A) j and k are both even: not necessarily true, for example \(j=1\) and \(k=1\);
(B) j = k: not necessarily true, for example \(j=3\) and \(k=1\);
(C) If j is even, k is even: as \(j^2=k*odd\) then in order \(j\) to be even \(k\) must be even too, so this statement must be true;
(D) j is divisible by k: not necessarily true, for example \(j=3\) and \(k=9\);
(E) j^2 > k: not necessarily true, for example \(j=1\) and \(k=1\).

Answer: C.