Which Statement Below Is True About the Instantaneous Rate for the Chemical

Which statement below is true about the instantaneous rate for the chemical reaction A $\rightarrow$ B as the reaction progresses?

A) (- $\Delta$ [A]/ $\Delta$ t increases while $\Delta$ [B]/ $\Delta$ t decreases.)
B) (- $\Delta$ [A]/ $\Delta$ t decreases while $\Delta$ [B]/ $\Delta$ t increases.)
C) Both- $\Delta$ [A]/ $\Delta$ t and $\Delta$ [B]/ $\Delta$ t decrease.
D) Both- $\Delta$ [A]/ $\Delta$ t and $\Delta$ [B]/ $\Delta$ t increase.
E) The answer will vary depending on the reaction mechanism.