Doubts from Geometrical isomers

Why first compound does not show GI but compound B shows?
A) Capture

B)Capture

anyone?

Because a has plane of symmetry while b does not

Do we need to consider about plane of symmetry in G.I?

I think you are commrnting about optical activity

Yes I think we consider pos in gi. I used to solve the problem using it.

You will many compounds showing GI though they have POS.
for example , in below compound you will find symmetry in a plane passing through R AND H
download

Anyone?