The correct option is C They are opaque and dark
The thorax region in the cockroach bears two pairs of wings - forewings and hindwings.
The forewings arise from the mesothorax. They are dark, opaque and cover the hindwings when at rest. The forewings are also called tegmina and do not help in flight.
The hindwings arise from the metathorax. They are light, transparent and membranous. The hindwings are used for flight.