Problem

If the angles

A, B

and

C

of a triangle are in an arithmetic progression and if

a, b

and

c

denote the lengths of the sides opposite to

A, B

and

C

respectively, then the value of the expression

\frac{a}{c} \sin 2C + \frac{c}{a} \sin 2A

is a.

\frac{1}{2}

\frac{\sqrt{3}}{2}

c. 1 d.

\sqrt{3}