What is the part of the speech of “But” in this sentence?
“These commands are binding on all children; they cannot be neglected without sin. Whatever God has commanded us to do, we must perform, without calling in question the propriety of the command.
But the reasonableness of this command to obey parents is clear and easily understood by children, even when quite young.”
(The word “But” is a start of the new paragraph and sentence according to the sentence above. “Reasonableness” is a noun, so should it be preposition or conjunction? Because “but” could be preposition or conjunction...For me, I think it is a preposition...I’m not sure🤔)