Question

Please friends help me to find the answer of the question in that figure.

Answer 1

angle CAO= angle OAB
here
angle BOD=90° so
angle DBA= BOA
it's mean that rays CA and BD is perpendicular to line AB
.
so CA is parallel to the reflected ray BD

Answer 2

Angle DBO = Angle ABO
Angle CAO = Angle BAO

(Angle of incidence = Angle of reflection)

In triangle AOB,
Angle BOA + Angle OBA + Angle OAB = 180 ( Angle Sum Property)

90 + Angle OBA + Angle OAB = 180
Angle OBA + Angle OAB = 90.

Multiply both sides by 2

Therefore,
2OBA + 2OAB = 2*90
Angle ABD + Angle BAC = 180

Therefore, BD||AC as these angles form co-interior angles and BA as transversal.