Correct!

You only have access to a local lab containing minimal equipment: a microscope and some reagents. Considering both your remote geographical location and the distinguishing characteristics of this disease, how would you confirm your diagnosis?

A.	Gram stain a smear of peripheral blood Bacillus anthracis usually causes septicemia so you should be able to find the organism in a smear of peripheral blood. A Gram-stain is very fast and doesn't require more than a few simple reagents and a microscope.
B.	Determine the antibody titer against B. anthracis Anthrax is an acute disease and animals die within hours after onset. Therefore, you would not expect to find antibodies as an immune response takes at least a couple of days to produce detectable levels. Furthermore, testing for antibodies is a complex procedure requiring equipment and reagents which would not be readily available.
C.	Test blood samples for the very potent anthrax-toxin in tissue culture One would expect to find anthrax-toxin in serum or plasma, but demonstrating it would also require equipment and reagents which would not be readily available.
D.	Culture the organism on selective media You would expect to be able to isolate B. anthracis, again, if you had the necessary growth media and access to an incubator.