[单选题]
In a first order reaction, the concentration [A] of a given reac+u-j jig 3pna:3y68jzymq)ywtant 6wqqt jf5mrkua 023wg kv;fo-a5+w9a can be determined at time t, according to the equation below, wh maqv9a 5gkr+kf06tfww -u w5a;j3o2qere [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
