Task: Question Answering
Input (English): Problem: during the last 4 years, a large truck company purchased diesel at rates of $ 1.2, $ 1.3, $ 1.8 and $ 2.1 per gallon. what was the mean cost of diesel over the 4 - year period if the company spends the same amount of dollars on diesel each year ?
Options: a. $ 2.5, b. $ 2.55, c. $ 1.52, d. $ 3.25, e. $ 3.0
Output (English): c