D. <em>uncharitable</em>.
The suffix <em>-able</em>, borrowed from Old French and originally from the Latin <em>-ābilis</em> (meaning "worthy of being acted upon"), can have different meanings.
The most common one is "fit/liable to be (done)," as in:
- <em>likeable</em> - fit to be liked
- <em>washable</em> - fit to be washed
- <em>degradable</em> - liable to be degraded.
This, however, does not apply to <em>comfortable</em>. Another meaning of <em>-able</em>, however, is "giving, or inclined to," as in:
- <em>comfortable</em> - giving comfort
- <em>(un)charitable</em> - (not) inclined to charity.
