Bob and Bill are preparers for the same tax preparation firm. Bob anticipates preparing $15$ returns during the tax filing season and ends up preparing only $9.$ Bill anticipates preparing $10$ returns but ends up preparing $12.$ Under these circumstances

Only the returns prepared by Bob must be e$-$filed

Only the returns prepared by Bill must be e$-$filed

All of the returns prepared by both Bob and Bill must be e$-$filed

Neither the returns prepared by Bob nor those prepared by Bill must be e$-$filed