In the triangle ABC , Angle ACB = 90 degree (Angle Subtended by the Diameter = 90 degree)

AC = 5cm

AB = 6.5 * 2 = 13 cm

using Pythagoras theorem

$AB^{2} = AC^{2} + CB^{2}$

$CB = \sqrt{13^{2} - 5^{2}}$ = 12

Area of triangle ABC = 0.5 * AC * CB = 30 sq.cm.

**Option B is the Correct Answer.**