Lyme disease used to be geographically restricted to the northeastern united states but has since soread significantly. this makes lyme disease an example of

a) a progressive virus
b) a bacteriophage
c) an emerging disease
d) a retrovirus

(C). an emerging disease.

Explanation:

Emerging disease can be defined as a disease, which has recently infected people of a population or disease whose geographic range or incidences are rapidly increasing in the near future.  

Previously, Lyme disease was geographically restricted to to the north-east United States, but now it is spreading significantly to the other regions. This makes it an example of an emerging disease.

Thus, the correct answer is option (C).

if you look up in the top right corner you'll see your current profile picture, click than click "view profile" you'll be able to change it there.