Step 1: Time to reach \(\frac A2\)
With \(x=A\sin\omega t\), \(x=\frac A2\) when \(\omega t=\frac\pi6\), so \(t=\frac{T}{12}\).
Step 2: Find \(T\)
\(\frac{T}{12}=2\) s gives \(T=24\) s.
Step 3: Time from \(\frac A2\) to \(A\)
Time from \(0\) to \(A\) is \(\frac T4=6\) s. So the time from \(\frac A2\) to \(A\) is \(6-2=4\) s. Option (D).
Final Answer:
The time is \(4\) s, option (D).
\[ \boxed{\text{(D) }4\text{ s}} \]