Three parter will give brainliest

To solve this problem you must apply the proccedure shown below:
 You have the equatio h=7Cos(πt/3), therefore:
 a) h=7Cos(πt/3)
 Cos(πt/3)=h/7
 Cos^-1(h/7)=πt/3
 t=(3/π)(Cos^-1(h/7))
 b)h=1
 t=(3/π)(Cos^-1(1/7))
 t=78.10
 h=3
 t=61.71
 h=5
 t=42.41
 c) h=-1
 t=93.79
 h=-3
 t=110.18
 h=-5
 t=129.47 

The answer would be c