Take note that this is an isosceles triangle. This means that the A and C angles are the same with each other. These angles are equal to 70 Degrees. To solve this, start with 180 Degrees then subtract 40 degrees so that you will get 140 Degrees. You can divide this into two which means that you will get 70 Degrees.
The angle bisectors are AM and CM. They need to be divided into half. So from 70 Degrees divided into 2, you will get 35 Degrees. This means that the final equation will be 180 Degrees minus 35 Degrees minus 35 Degrees again in order to get the answer of 110 Degrees. This means that the answer is A.