IMO, I do not agree with B. My pick is D.
First of all,
"require X to do Y" is subjunctive form, so I eliminated A, C, E. Only B and D remain. Let analyze each option:
Management is considering a policy requiring employees provide doctors' notes after taking sick leave so as to prove fitness to return to work. a-provide doctors' notes after taking sick leave so as to
Wrong. Subjunctive form: require X to do Y
b-to provide doctors' notes after taking sick leave so as to
Wrong. - The structure is like: "
Management requires
employees to provide doctor's notes ...
so as to prove fitness..." It's quite not clear, who will prove fitness? management or employees?.
- From my experience, "so as to" is not preferable to "so that" or "in order to" in GMAT (this is not a rule, just my experiences).
c-provide doctors' notes after taking sick leave in order that they
Wrong. Subjunctive form: require X to do Y
d-to provide doctors' notes after taking sick leave so that the employees can
Correct IMO. The present of subject "the employees" after "so that" is very clear.
e-provide doctors' notes after taking sick leave and
Wrong. Subjunctive form: require X to do Y
Waiting for OA.