(a) The county clerk has the duty to take the probate or acknowledgment of all deeds and other instruments that are entitled to registration by law, and to certify the same for registration, and to demand and receive the state tax thereon, as specified in title 67, chapter 4, part 4.
(b) Subsection (a) shall only apply in counties having a population, according to the 2000 federal census or any subsequent federal census, of:
(c) In counties having a population of not less than thirty-nine thousand fifty (39,050) nor more than thirty-nine thousand one hundred fifty (39,150), according to the 2000 federal census or any subsequent federal census, the circuit court clerk, who also serves as the general sessions court clerk, shall serve as the clerk of the court with probate jurisdiction in any such counties.