Get a B or get a W in premed course (and I already have lots of W\'s from UG)

Is it better to get a W in a course than get a B grade?
I am taking the third quarter class of general biology and, of all the biology courses that I have taken, this one has been the hardest. What makes it hard is not the material, but how we are being tested on that material and the fact that we only have one midterm and one final examination. Most of our exams are True / False questions and I find this sort of questioning difficult and much harder than essay examinations or diagrams, etc. On the one and only midterm, I received a low C, meaning that even if I ace the final examination (not likely given how I did on this midterm), the best grade that I could do in the course is a B.

I’ve worked too hard in this class to get a B.

So, if I drop the course now, I would get a W. I already have many W’s from undergraduate (I went to undergrad twice, and have two bachelor’s degrees).

Any feedback on this?

I should also add, that my poor grades in this class are not only due to the testing style, of which I am not used to. I have also missed several classes due to my volunteer medical work (which takes me out of the U.S.) and on the days on which I have been gone abroad, we have had discussion sessions. So, I’ve lot points for lack of attendance on those days. Also, my job and the commute (3.5 hours per day commuting to and from class) takes up more time, so I find myself constantly catching up. I would like to move closer to school, but I cannot afford the ridiculous rent on my salary.