The man began to cogitate about cogitating, being able to do this meant he clearly he must what?\nOptions:\n- obsessive compulsive\n- mad\n- perambulate\n- have brain\n- sit quietly
Step-by-step reasoning:
have brain
Person who cogitate keeps on thinking very deeply.

Only intelligent persons can cogitate about cogitating.

Intelligent persons must have brain to think.

.

Therefore, the answer is have brain