Final answer:
The section of the Mass with Greek text is the Kyrie, which stands out from the other Latin-text sections like the Gloria, Agnus Dei, and the Credo.
Step-by-step explanation:
The section of the Mass which contains Greek text is Kyrie. The Kyrie consists of the phrase 'Kyrie eleison' (Lord, have mercy), which is often chanted or sung during the liturgy. Unlike the other parts of the Mass such as the Gloria, Agnus Dei, and the Credo (Nicene Creed), the Kyrie is unique for its use of Greek language in the predominantly Latin rite of the Catholic Mass. The Nicene Creed formulated at the Council of Nicaea, as you mentioned, is a profession of faith in Christ's divinity and an essential element of Catholic doctrine but is in Latin, not Greek. Therefore, the correct answer to your question is A. Kyrie.