If a * b = a + b + ab, then 3 * 4 - 2 * 3 is equal to?

Answer: Option B

$$\begin{array}{rl}& a\ast b=a+b+ab\\ & 3\ast 4\\ & =3+4+3\times 4\\ & =19\\ & 2\ast 3\\ & =2+3+2\times 3\\ & =11\\ & \therefore 3\ast 4-2\ast 3\\ & =19-11\\ & =8\end{array}$$