Answer:d
Step-by-step explanation:
Drift velocity is given by
![v_d=(I)/(n* Q* A)](https://img.qammunity.org/2021/formulas/physics/high-school/ph2wo4l5nlzmxeyyj0x1d7feoasc6nt0nf.png)
where
=drift velocity
I=Current
n=no of electron
Q=charge of Electron
A=cross-section
If area of cross-section decreases gradually then drift velocity will increase because drift velocity is inversely proportional to Area of cross-section