ABC is an isosceles triangle whose side have length 5 and 6. What can be the area of triangle ABC, if the altitude from the base of ABC is an integer ?

Question

$\begin{array}{1 1} (a)\; 12\; sq. units\\(b)\; 15 \;sq. units \\ (c)\; 10\; sq. units\\ (d)\; 20 \;sq. units \end{array}$