The intermediates involved in the following reaction are

Concept:-

Ring-closing metathesis:

• Ring-closing metathesis (RCM) is a widely used variation of olefin metathesis in organic chemistry for the synthesis of various unsaturated rings via the intramolecular metathesis of two terminal alkenes, which forms the cycloalkene as the E- or Z- isomers and volatile ethylene.
• An example is shown below:

Explanation:-

• The reaction pathway is shown below:

Conclusion:-

Hence, the intermediates involved in the following reaction are A and B