Find the variation constant and an equation of variation in which y varies directly as x, and y = 42 when x = 3.

a) Variation constant: 14, Equation: y = 14x
b) Variation constant: 14, Equation: y = 42x
c) Variation constant: 12, Equation: y = 12x
d) Variation constant: 12, Equation: y = 42x