[单选题]
In a first order reactv*n s hor)wlh73fhb8 6ion, the concentrati f ald/t3bv7y3on [A] of a given reactant can be determined at time t, according to the3y3 l 7vabdft/ equation below, where [A]$_o$ is the initial concentration of A and k is the rate constant.
ln[A]=-kt+ln[A]$_o$
A. Independent variable
B. Dependent variable
C. y-intercept
D. Gradient
