Really easy problem but it is a substantive basis for endgame moves.
(;AW[so]AW[rn]AW[qn]AW[pn]AW[om]AW[oo]AW[pp]AW[pq]AW[pr]AW[nm]AB[sn]AB[sm]AB[rm]AB[qm]AB[pm]AB[ol]AB[pk]AB[qh]AB[or]AB[oq]AB[np]AB[lq]AB[jq]C[What is the most efficient way to answer 3 ?]LB[sn:1]LB[so:2]LB[sm:3]AP[goproblems]
(;W[rr]C[By playing this, the move in A will be Gote for your opponent.RIGHT]LB[ps:A])
(;W[ro];B[ps];W[qs];B[os]
(;W[qr])
(;W[rr]))
(;W[rp];B[ps];W[qs];B[os]
(;W[qr])
(;W[rr])))