OERecall that
\((-1)^p =\) { 1 if p is an even integer and -1 if p is an odd integer}
Since \(p = r^2 + t,\) the value of (-1)p depends on whether \(r^2 + t\) is odd or even.
If r is an odd integer, then \(r^2\) is an odd integer and, since r and t are consecutive integers, t is an even integer. In this case, p is the sum of an odd integer and an even integer and is therefore an odd integer.
Similarly, if r is an even integer, then \(r^2\) is an even integer and t is an odd integer. In this case, p is the sum of an even integer and an odd integer and is therefore an odd integer.
In both cases, p is an odd integer. It follows that \((-1)^p = -1,\) and the correct answer is Choice C.