Final answer:
The given options are not equivalent to the expression 3/75a^7b^4, and it seems there may be a typo in the original expression. To find an equivalent, clarification is needed as none match the form or variables of the original.
Step-by-step explanation:
The expression equivalent to 3/75a^7b^4 is not presented in the given options of a), b), c), or d). To find an equivalent expression, you would simplify the fraction by dividing both the numerator and the denominator by their greatest common divisor. However, the options given do not simplify down from 3/75a^7b^4 or they involve different variables and exponents not present in the original expression. Depending on the typo mentioned in the question, it could imply that the original expression is not accurately provided, or none of the options are correct. If the expression was meant to be something else, the question would need clarification for a precise equivalent to be determined.