Lord Buddha's image is sometimes shown with the hand gesture called' Bhumisparsha Mudra'. It symbolizes

(a) Buddha's calling of the Earth to watch over Mara and to prevent Mara from disturbing his meditation
(b) Buddha's calling of the Earth to witness his purity and chastity despite the temptations of Mara
(c) Buddha's reminder to his followers that they all arise from the earth and family dissolve into the Earth, and thus this life is transitory
(d) Both the statement (a) and (b) are correct in this context