Darcy, age 7 years, falls down the stairs while playing at a friend's house. He fractures tooth 1-1 and tooth 2-1 is knocked out completely. Darcy is immediately transported to the hospital dental department for treatment. Clinical examination of Darcy's injury reveals an extensive fracture to tooth 1-1 with pulpal exposure. The root of Darcy's tooth 1-1 has an open apex, as the apical constriction is not complete. The procedure of choice would be ________
a. apexogenesis.
b. apicoectomy.
c. root canal therapy.
d. pulpectomy.