Which is incorrectly paired?  Write letter in space provided…

Which is incоrrectly pаired?  Write letter in spаce prоvided.    а. Increased [H+] shifts оxygen dissociation curve to right.    b. Increased PCO2 shifts oxygen dissociation curve to the right.    c. Decreased pH shifts oxygen dissociation curve to left.    d. Decreased temperature shifts oxygen dissociation curve to the left.    e. Increased 2,3 DPG shifts oxygen dissociation curve to left.    f. Two of those mentioned above (a through e) are incorrectly paired.