Task: Question Answering
Input (English): Question: David invested a certain sum of money in a bank that paid simple interest. The amount grew to $300 at the end of 2 years. He waited for another 3 years and got a final amount of $390. What was the principal amount that he invested at the beginning?

 Option A: $340

 Option B: $300

 Option C: $280

 Option D: $260

 Option E: $240
Output (English): Option E