Which of the following sentences does NOT illustrate proper use of articles and conjunctions?

Which of the following sentences does NOT illustrate proper use of articles and conjunctions?

A. I thought about keeping an orangutan as a pet; however, my apartment complex does not allow exotic animals on the premises.
B. Bertha decided to change a locks of her house after burglars stole a computer or an oil painting.
C. After thinking about the problem for half an hour, Glen finally came up with a perfect solution.
D. Arlene loves nature and the outdoors in general, yet she spends most of her time inside because of her job.

Answer - B