Crank pin effort in a reciprocating engine is:

(a) \(\frac{F \sin (\theta+\phi)}{\cos \phi}\)

(b) \(\frac{F \sin (\theta+\phi)}{\sin \phi}\)

(c) \(\frac{F \cos (\theta+\phi)}{\cos \phi}\)

(d) \(\frac{F \cos (\theta+\phi)}{\sin \phi}\)

where \(F=\) piston effort