What external changes are visible after the last moult of a cockroach nymph?

The cockroach life cycle actually has three developmental stages. These stages are known as the egg, the nymph and the adult stages. Each time the molting process is completed the cockroach will get bigger, change in colour and look more like an adult cockroach. The nymph stage of the cockroach life cycle can take anywhere from a month and a half to several years, depending on the environment. After the final moult the nymph bears wings. When the cockroach reaches its adult size it will not moult again. Cockroaches complete their transformation into adulthood with a pair of wings - forewings and hind wings. So, the correct answer is option D.