Who, according to the Buddhist, is believed to be the next incarnation of Gautam Buddha?

Answer: Option B

According to Buddhist tradition, Maitreya is a bodhisattva who will appear on Earth in the future, achieve complete enlightenment, and teach the pure dharma. According to scriptures, Maitreya will be a successor to the present Buddha, Gautama Buddha (also known as Sakyamuni Buddha).