Morphine, a pain killer is basic with the molecular formula $$\text{C}_{17}\text{H}_{19}\text{NO}_3$$. The conjugate acid of morphine is

A

$$\text{C}_{17}\text{H}_{19}\text{NO}_3^+$$

B

$$\text{C}_{17}\text{H}_{18}\text{NO}_3$$

C

$$\text{C}_{17}\text{H}_{19}\text{NO}_3^-$$

D

$$\text{C}_{17}\text{H}_{20}\text{NO}_3^+$$