Write an equation of the sine function.. amplitude: 4, period: pi, phase shift: -1/6 pi, vertical shift: -1

The standard form of equation for the sin function is y = Asin(Bx-C) where A is amplitude, Period is 2π/B, and the phase shift is equal to Bx-C set to zero. C is then obtained in this equation.

For given problem: A is equal to 4, period=2π/B=2π/2=π, where B is equal to 2 and the phase shift is equal to 2x - 1/12 pi =0 
y = 4 sin (2x- 1/12 pi) -1 

The answer is option c.