Answer:
A
Step-by-step explanation:
The standard equation of proportion is
y = kx ← k is the constant of proportionality
A
y = 5x is in this form with k = 5
B
y = [tex]\frac{10}{5}[/tex] x = 2x with k = 2 ≠ 5
C
y = [tex]\frac{5}{25}[/tex] x = [tex]\frac{1}{5}[/tex] x with k = [tex]\frac{1}{5}[/tex] ≠ 5
D
y = [tex]\frac{1}{2}[/tex] x with k = [tex]\frac{1}{2}[/tex] ≠ 5
