Final answer:
The equation 'X + Y = Z' is represented directly by option C. X + Y = Z. Matching the equation to the correct form is crucial in identifying the right representation.
Step-by-step explanation:
The equation that represents X + Y = Z is C. X + Y = Z. When dealing with equations, it is important to match the exact form of the expression on one side of the equation with the corresponding variables on the other side. Options A, B, and D represent different equations and relationships between their respective variables and cannot be the correct representation of X + Y = Z.