A risk corridor is one of the main provisions, albeit not the only one, that protects the insurance industry from hitting rock bottom, like it did earlier in the decade.
A. protects the insurance industry from hitting rock bottom, like it did
B. protect the insurance industry from hitting rock bottom, as it did
C. protects the insurance industry from hitting rock bottom, as it did
D. protect the insurance industry from hitting rock bottom, like
E. protect the insurance industry from hitting rock bottom, like they did

OA : B

My question is Should it not have been protects over here since the subject a risk corridor is singular?