LetL(r) be the amount of lumber, in board-feet, that can be produced from atree of radiusr(in inches).

Let L(r) be the amount of lumber, in board-feet, that can be produced from a tree of radius r (in inches). For a tree with a radius of 10 inches, the amount of lumber that can be produced is increasing with respect to the radius at a rate of 140 board-feet per inch of radius.

Choose the mathematical expression that matches this statement.

L'10 = 140

L(10) = 140

L(140) = 10

L'(10) = -140

L'(140) = 10