Answer=B
a.) The period creates two fragmented/incomplete sentences.
b.) B is correct
c.) It is incorrect to put periods after the abbreviations of states.
d.)The sentence should read, '45mph', writing 'm.p.h.' is inaccurate.
The b best answer that I could see is D because it correlates to the actual question. But c also looks good because it gives a reason as why not to buy them from a shop/private owner.
Best of Luck...Nathan...L.
