(4.04 LC)

Which equation represents a linear function?

Equation 1: y3 = 2x + 1
Equation 2: y = 3x + 1
Equation 3: y = 5x2 − 1
Equation 4: y = 4x4 − 1

A. Equation 1
B.Equation 2
C. Equation 3
D. Equation 4