Final answer:
The ROMI can be calculated by dividing the incremental revenue by the marketing cost. In this case, the ROMI is 375%.
Step-by-step explanation:
The ROMI (Return on Marketing Investment) can be calculated by dividing the incremental revenue by the marketing cost.
In this case, the incremental revenue is $30,000 (revenue attributable to the radio ad) and the marketing cost is $8,000 (cost to develop and play the ad).
The ROMI can be calculated as follows:
ROMI = (Incremental Revenue / Marketing Cost) * 100
ROMI = ($30,000 / $8,000) * 100
ROMI = 375%
Therefore, the correct answer is a. 357%.