Answer:
i think its

Step-by-step explanation:
Answer: see proof below
<u>Step-by-step explanation:</u>

Use the following Identities:
sec Ф = 1/cos Ф
cos² Ф + sin² Ф = 1
<u>Proof LHS → RHS</u>






Step-by-step explanation:






Taking sin²θ common in both numerator & denominator, We get :










<u>Hence</u><u>,</u><u> option</u><u> </u><u>(</u><u>a)</u><u> </u><u>2</u><u>/</u><u>3</u><u> </u><u>is </u><u>your</u><u> </u><u>correct</u><u> </u><u>answer</u><u>.</u>