(answer + ! ) oil and gas production in a certain area dropped from 4 million barrels in 2000 to 1.9 million barrels in 2013. assuming that the oil and gas production decreased at a constant rate, which of the following linear functions f best models the production, in millions of barrels, t years after the year 2000? a. f(t) = 21/130t + 4 b. f(t) = 19/130t + 4 c. f(t) = -21/130t + 4 d. f(t) = -19/130t + 4