If 1 - + 1 + sin = 4, then the value of ( 0^ < < 90^ ) is?

Answer: Option A

$$\begin{array}{rl}& \Rightarrow \frac{\cos \theta }{1-\sin \theta }+\frac{\cos \theta }{1+\sin \theta }=4\\ & \Rightarrow \cos \theta \left(\frac{1+\sin \theta +1-\sin \theta }{1-{\sin }^2\theta }\right)=4\\ & \Rightarrow \cos \theta \left(\frac{2}{\text{co}{\text{s}}^2\theta }\right)=4\\ & \Rightarrow \cos \theta =\frac{1}{2}\\ & \Rightarrow \theta =60^{\circ }\end{array}$$