The correct option is A 1
Sa3(150πt)→ωm1=3×150π=450π rad/sec
Sa2(200πt)→ωm2=2×200π=400π rad/sec
for (f1(t)∗f2(t))→ωmf=min{ωm1,ωm2}=400π rad/sec
Sa3(200πt)→600π
Total band width = 400πt+600πt=1000πt
Nyquist frequency = 1000π rad/sec
Nyquist interval , TN=2π2000π = 1 m sec
Nyquist interval , TN=πωm=π1000π=1msec