Answer: The correct option is fourth,i.e., x=40.
Step-by-step explanation:
First of all mark the names of all vertices of the triangle as shown in below figure.
From the figure it is noticed that the angle ACB and the angle ACD lie on a straight line. so, both angles are supplementary angles and their sum is 180 degree.



Divide both sides by 5.

Therefore x=40 is a correct value of x and correct option is fourth.