When someone quotes a verse to support a particular point they should carefully consider the context. Read a few vss, before and after. You didn't do that.
But I have.
And I believe "the Lord" in 2 Corinthians 3:17 refers to the Person Yahweh.
I was not able to discern your answer. Are you able to pick an answer from the options below. Your fellow Trinitarian @johnny guitar says C.
Which Divine Person(s) does "the Lord" in 2 Corinthians 3:17 refer to?
2 Corinthians 3:17... Now the Lord is that Spirit: and where the Spirit of the Lord is, there is liberty.
A) the first Person of the Trinity
B) the second Person of the Trinity
C) the third Person of the Trinity
D) the first and second Persons of the Trinity
E) the first and third Persons of the Trinity
F) the second and third Persons of the Trinity
G) all three Persons of the Trinity
H) not sure which Person(s)
I) no Person, just the Substance of the Trinity
J) no Person or Substance, just something else