What are the points on the curve $x^2+y^2-2 x-3=0$ where the tangents are parallel to $x$-axis?

• Correct answer
  A

  $(1,2)$ and $(1,-2)$
• B

  $(0, \sqrt{3})$ and $(0,-\sqrt{3})$
• C

  $(3,0)$ and $(-3,0)$
• D

  $(2,1)$ and $(2,-1)$

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