Maximum speed of wave is given as vmax=ωA = Angular speed × Amplitude Thus, In option (a) y(x,t)=2sin‌(2x−2t) ‌A=2,ω=2 ∴‌‌vmax=2×2=4m∕s In option (b), y(x,t)=3sin‌(2x−3t) A‌=3,˙ω=3 ∴‌‌vmax‌=3×3=9m∕s In option (c),y(x,t)=2sin‌(3x−2t) A=2,ω=2 ∴vmax=2×2=4m∕s In option (d), y(x,t)=3sin‌(5x−2t) A‌=3,ω=2 ∴‌‌vmax‌=3×2=6m∕s Clearly, wave speed is maximum as 9m∕s in wave equation given in option (b).