The missing character is $\boxed{\text{J}}$.
The sequence is a list of letters, each of which is one letter after the previous letter in the alphabet. The first letter is $\text{A}$, the second letter is $\text{B}$, and so on. The missing letter is the letter that comes after $\text{I}$ in the alphabet. This letter is $\text{J}$.
The other options are incorrect because they are not letters that come after $\text{I}$ in the alphabet. Option $\text{F}$ is the letter that comes after $\text{E}$ in the alphabet. Option $\text{N}$ is the letter that comes after $\text{M}$ in the alphabet. Option $\text{S}$ is the letter that comes after $\text{R}$ in the alphabet. Option $\text{D}$ is the letter that comes after $\text{C}$ in the alphabet.