Final answer:
The equation A) Y = 4x represents a proportional relationship, where 'Y' changes in direct proportion to 'X' with 4 being the constant of proportionality.
Step-by-step explanation:
The equation that represents a proportional relationship is A) Y = 4x. A proportional relationship is one where two quantities vary directly with each other, which means if one quantity changes, the other changes in proportion to the first. This relationship can be described by the equation y = kx, where k is the constant of proportionality. In this case, the constant k is 4. Options B, C, and D involve additional terms added or subtracted from the independent variable x, which indicates that they do not represent a direct proportion and therefore do not represent a proportional relationship.