I need help is it A B C or D

Answer fast please

Ineed someone to me answer my question i have to have this done and knocked out

Will mark ! (10 points also! ) if x varies inversely with y and x =6 when y= 10, find y when x=8 a. y=4.8 b. y=7.5 c. y=40/3 d. y=4/15

The power generated by an electrical circuit (in watts) as a function of its current c (in amperes) is modeled by p(c)= -15c(c-8) what current will produce the maximum power?