Is the Following Syllogism Valid? Either There Is an Accounting

Is the following syllogism valid? Either there is an accounting error, or some of our members are not paying their dues.
All of our members are paying their dues.
There is an accounting error.

A) Yes.
B) No, because the disjunctive premise is not in standard form.
C) No, because the second premise does not deny any of the disjuncts.
D) No, because even if the premises are true, the conclusion could be false.
E) It depends on your view of existential import.