Correct Answer  Option 3 : Aω
^{2}
CONCEPT:

Simple harmonic motion is the repetitive motion of a body back and forth about an equilibrium point. \
 The force which executes this motion is given by
⇒ F = kx
Where k = spring constant, x = Position
 The position of a simple harmonic motion is given by
⇒ x = A Cos (ωt + Φ)
Differentiating the above equation the velocity can be written as
⇒ V = AωSin(ωt + ϕ)
Differentiating the above equation we get the acceleration as
⇒ a = ω^{2}Cos(ωt + ϕ)
 in a simple harmonic motion, the acceleration is directed towards the center
CALCULATION:
Given  y = A Sinωt+BCosωt
\(\Rightarrow V = \dfrac{dy}{dt} = \dfrac{d(A Sinω t+B Cosω t)}{dt}\)
⇒ V = A ω Cos ωt Bω Sin ωt
Again differentiating the above equation with respect to t
\(⇒ a = \dfrac{dV}{dt} = \dfrac{d(A ω Cos ω t  B ω Sinω t)}{dt} =  Aω \times ω Sinω t  Bω\times ω Cosω t\)
⇒ a =  Aω^{2}Sin ωt B ω^{2}Cosωt
Substituting the value \(\omega t = \dfrac{\pi}{2}\)
⇒ a = A ω^{2}
 Hence, option 3 is the answer