This situation occurred in a game I played recently, and should be pretty easy. Please let me know if I've messed anything up!
(;AW[ro][so][pp][qp][nq][oq][pr][os]AB[rp][sp][pq][qq][qr][rr][qs]C[Best play for White?](;W[sr];B[ss](;W[rs]C[RIGHTIt's a ko for life. White captures first, so Black must find the first threat.])(;W[sq];B[rq])(;W[rq];B[sq])(;W[ps];B[sq])(;W[or];B[sq]))(;W[sq];B[rq]LB[sr:A][ss:B]C[Black is alive. Next, if White plays A, Black can make two eyes at B, and vice versa.])(;W[rq];B[sq])(;W[rs];B[ss])(;W[ss];B[sr])(;W[ps];B[sr]))