The set of all x in the interval [0, π] for which 2 sin^2 x - 3 sin x + 1 ≥ 0 is?

I got three values of x:

π/6, 5π/6 and π/2

Options for the question are:

A) [π/6, 5π/6] U {π/2}

B) [π/6, 5π/6] - {π/2}

C) [π/6, 5π/6]

D) None

What is the correct option? And can someone explain the methodology behing representing the values in an interval or set?