Consider the two statements
R: $\quad k$ is an integer multiple of $\pi$
$$\mathrm { S } : \quad \int _ { 0 } ^ { k } \sin 2 x \mathrm {~d} x = 0$$
Which of the following statements is true?
A $R$ is necessary and sufficient for $S$.
B R is necessary but not sufficient for $S$.
C R is sufficient but not necessary for $S$.
D $R$ is not necessary and not sufficient for $S$.