Jared is taking diving lessons and starts 20 feet below sea level. he then dives down another 10 feet. from there, he goes up 15 feet. which equation shows jared's current level?
a.-20 + 10 + 15 = 5
b. 20 + (-10) + (-15) = -5
c. -20 + (-10) + (-15) = -45
d. -20 + (-10) +15 = -15