Correct Answer - Option 2 : 9
Concept used :
sin2 θ = 1 - cos2 θ
Calculations :
9 sin2 θ + 16 cos2 θ = 9 sin2 θ + 16 ( 1 - sin2 θ)
⇒ 9 sin2 θ + 16 - 16 sin2 θ
⇒ -7 sin2 θ + 16
⇒ -7 + 16 (for least value of the equation value of sin2 θ must be equal to 1)
⇒ 9
∴ Option 2 will be the correct choice.