Assertion: According to Hugo de Vries, evolution is a gradual and continuous process

Reason: He believed that accumulation of smaller mutations over several generations is responsible for evolution

The correct option is D Both assertion and reason are false
Hugo de Vries proposed the mutation theory. According to Hugo de Vries, single step large mutations (saltations) are responsible for the appearance of new variants that form entirely new species in a single generation. Hence, he believed that evolution is not a gradual process.

On the other hand, Darwin’s theory states that new variations appear in every generation and they supplement the inherited variations, i.e., they have an additive effect. Such small variations accumulate over several generations by natural selection until the offspring become significantly different, thus evolving into a new species.

Thus, both the assertion and the reason are false.