The angles of a triangle are in AP and the least angle is $30^{\circ}$. What is the greatest angle (in radian)?

• Correct answer
  A

  $\frac{\pi}{2}$
• B

  $\frac{\pi}{3}$
• C

  $\frac{\pi}{4}$
• D

  $\pi$

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