The pH of the solution produced by complete consumption of 10 mL of 0.4 M NaOH to 'x' mL of 0.5 M $$\text{CH}_3\text{COOH}$$ was found to be 4.57. The value of 'x' (mL) is, given that $$K_a$$ of $$\text{CH}_3\text{COOH} = 1.8 \times 10^{-5}$$

A

12.0

B

10.4

C

19.8

D

6.5