The expression - 280 + 15x represents a submarine that began at a depth of 280 feet below sea level and ascended at a rate of 15 feet per minute. What was the depth of the submarine after 7 minutes?
Select the correct answer below and, if necessary, fill in the answer box to complete your choice.
A. The submarine was
s feet below sea level after 7 minutes.
OB. The submarine will have reached sea level after 7 minutes.