The cube of y varies directly as z. When y = 8, z = 8. Heather’s work finding the value of y when z = 64 is shown: y^3 = kz
8 = k x 8
1 = k

y^3 = 1 x 64
y^3 = 64
y = 4

What is the first error, if any, in Heather’s work?

A. She did not make any errors.
B. She substituted incorrectly when calculating the constant of variation.
C. She cubed the wrong variable when making her equation.
D. She used an equation that models inverse variation instead of direct variation.