The correct answer is A. 36°
Explanation.
All triangles have three internal angles. Additionally, in these, if you add the three internal angles the total is always 180°. This implies the first angle which is 79° added to the second angle, which is 65° and the third angle (value of x) should be equal to 180°. This can be solved by subtracting the two angles known from the total 180°.
x + 79° + 65° = 180
x = 180 -79°- 65°
x = 36°
Also, you can know this result is accurate because 36° + 79° + 65° = 180°