Real Bible Translation

And they questioned himself and are saying to himself, Who⁴³ therefore are you submerging⁴⁴ if you are not yourself, the Anointed One,⁴⁵ neither He Is God ("Elijah"), neither the Prophet?

Julia Smith Literal 1876 Translation:
And they asked him, and said to him, Why immersest thou then, if thou art not Christ, neither Elias, neither a prophet?

LITV Translation:
And they asked him and said to him, Why then do you baptize, if you are not the Christ, nor Elijah, nor the Prophet?

ESV Translation:
They asked him, “Then why are you baptizing, if you are neither the Christ, nor Elijah, nor the Prophet?”

Footnotes

Strong’s #G5101, tis. Who, which, what. This is the interrogative pronoun used for indirect questions. In multiple places the pronoun is interpreted as “why” based on the translator’s understanding of the context, but such use is rare in Classical Greek. Cf. , . “Rarely in indirect questions, , , .—Adv. , why? how?” - .

Strong’s #G907, baptizó. To dip under, sink, submerge. It originates from baptó (#G911) to dip and so we read,

“…that he might dip [baptó] the tip of the finger of himself of water…” Luke 16:24 literal

Strong’s #G5547, Christos. Xristós (from /xríō, ‘anoint with olive oil’) – properly, "the Anointed One," the Christ (Hebrew, ‘Messiah’).” Mashiach in Hebrew (#4899) means anointed one. It has to do with one who is anointed king.