The Vedic pantheon comprises a diverse set of deities, but the principal deities that played significant roles in Vedic rituals and hymns were as follows:

(A) Agni: Agni is the god of fire and a mediator between the human world and the divine. He is central to Vedic rituals and offerings.

(C) Indra: Indra is the god of thunder, rain, and the king of the heavens. He is one of the most prominent and revered deities in the Rigveda, and his role in providing rain and defeating demons is emphasized.

(E) Soma: Soma is associated with a ritual drink made from a plant and is personified as a deity. It played a central role in Vedic rituals and was believed to bestow divine powers and immortality.

(B) Vishnu and Shiva are important deities, but they gained more prominence in later Hindu traditions and are not typically considered principal deities of the Vedic pantheon.

So, the correct answer is (3) (A), (C), (E) Only, as these deities were among the most significant in the Vedic context.