In the given diagram, lines AB and CD are parallel. What is the angle 0?

Correct option is C

Given:

AB and CD are parallel.

Concept:

We will use the angle sum property.

Solution :

$$\begin{aligned}&\textbf{}\quad \angle BEC = \angle AED = 140 \quad \text{(Alternate exterior angle)} \\[6pt]&\angle AEB = \angle DEC \quad \text{(Alternate interior angles)} \\[6pt]&\angle DEC + \angle DEA + \angle AEB + \angle BEC = 360 \\[6pt]&\Rightarrow \angle AEB = 40 \\[6pt]&\angle B = \angle D = 75 \quad \text{(Vertically opposite angle)} \\[6pt]&\text{Using angle sum property:} \\[6pt]&\angle A + \angle B + \angle AEB = 180 \\[6pt]&\angle A = \theta = 180 - (40 + 75) = 180 - 115 = \boxed{65}\end{aligned}$$

Final Answer: C