In the given figure, the angles $\angle B A Q=$ $\angle C P Q=\angle C B Q=\frac{\pi}{2}$; and the lengths $Q A=3$ unit, $A B=4$ unit, and $B C=1$ unit. What is the length of $P Q$ ?

• A

  2 unit
• Correct answer
  B

  2.2 unit
• C

  $\sqrt{2}$ unit
• D

  $3-\sqrt{2}$ unit

Hence, the correct answer is option: 'B'.