A liquid flows in a tube from left to right as shown in figure.  ${\mathrm{A}}_1$ and  ${\mathrm{A}}_2$ are the cross-sections of the portions of the tube as shown. Then the ratio of speeds  ${\mathrm{v}}_1/{\mathrm{v}}_2$ will be

• A

  ${\mathrm{A}}_1/{\mathrm{A}}_2$

• B

  ${\mathrm{A}}_2/{\mathrm{A}}_1$

• C

  $\sqrt{{\mathrm{A}}_2}/\sqrt{{\mathrm{A}}_1}$

• D

  $\sqrt{{\mathrm{A}}_1}/\sqrt{{\mathrm{A}}_2}$