Answer:
The answer is option A.
p = 0.7(rh + b)
Making h the subject
divide both sides by 0.7
we get
p/0.7 = rh + b
send b to the left side of the equation
p / 0.7 - b = rh
divide both sides by r
we get
( p / 0.7 - b) ÷ r = h
therefore h = ( p / 0.7 - b ) ÷ r
Hope this helps