Which of the Following Is the Best Description of F'(t) $\frac { f ( t + h ) - f ( t ) } { h }$

Multiple Choice

Which of the following is the best description of f'(t) ?

A) It is a function which gives the slope of the secant line through any two points.
B) The derivative as a function is the best approximation of the tangent to line to f(x) .
C) It is approximately equal to $\frac { f ( t + h ) - f ( t ) } { h }$ , as t gets very small.
D) f'(a) measures the rate of change of f(t) per unit change in t at the point t = a.
E) f'(t) = $\frac { \mathrm { f } ( \mathrm { t } ) } { \mathrm { t } }$