How do you figure? There are not really a whole lot of Christian rituals. Baptism and the Lord's supper are the main two.
Baptism is linked to repentance and was preached by John the Baptist who was considered a prophet by many in the Jewish community.
The Lord's supper was commanded by Jesus Himself.
Hmmm. "Communion" is closely based on the "Last Supper" of Jesus---- the Passover Seder that took place the evening before the Romans soldiers crowned him with thorns, mocked and whipped him then nailed him to the execution stake. And Passover is no way based on Zoroastrianism.
"Baptism:" This is based on the Jewish ritual mikveh bath that represents cleansing or repentance. Next time you go to Jerusalem, check out the ruins of these baths just outside the current south wall of the city, between the "Dung" Gate and "Zion" Gate.
I don't believe the Zoroastrians practiced the salvation story of Passover, or an immersion of repentance. Please point me to where I can be disabused of this belief.