Given a math problem with context and a question and 5 answer choices, the task is to provide the correct answer choice based on the problem. You must choose one of the given answer choices by letter: a, b, c, d, or e; anything else is invalid.

Q: Problem: if an investor puts $ 800 in a savings account that earns 10 percent annual interest compounded semiannually, how much money will be in the account after one year ?
Options: a. $ 878, b. $ 880, c. $ 882, d. $ 884, e. $ 886

A: c
****
Q: Problem: evaluate: 98612 / 22 * 11 * 70 = ?
Options: a. 700.4, b. 704.4, c. 740.4, d. 744.4, e. 700.0

A: b
****
Q: Problem: robert ' s salary was increased by 50 % and subsequently decreased by 10 %. how much percentage does he gain ?
Options: a. 15 %, b. 20 %, c. 10 %, d. 25 %, e. 30 %

A:
a
****