Concept:The quadratic under the square root is a perfect square, so reduce it before solving for t.Explanation:Start with S=t2−4t+4.Factor the radicand: t2−4t+4=(t−2)2.Thus S=(t−2)2=∣t−2∣.This gives two possible branches: t−2=S or t−2=−S.Solving them gives t=S+2 or t=2−S.Among the given options, the one that matches is t=S+2.Answer:Option B: S+2.