A 25.5 mL aliquot of HCl (aq) of unknown concentration was titrated with 0.113 M NaOH (aq). It took 51.2 mL of the base to reach the endpoint of the titration. The concentration (M) of the acid was __________.
A) 1.02
B) 0.114
C) 0.454
D) 0.113
E) 0.227