"the intensity of a conviction that a hypothesis is true has no bearing on whether it is true or not"?

This was a quote from Peter Medawar. The British biologist was instrumental in the discovery of acquired immune tolerance, which has been the bedrock of the ability for patients to receive organ transplants. He was also one of the first to describe the evolutionary mechanisms behind senescence, or the decline of physical abilities that accompany the ageing process.

Ithink it's a, but i might be wrong