What does the word "En-Masse”refer to in the second line of the poem“One's Self I Sing”?

A、Peoplebandingtogethertoaccomplishanationalproject.;
B、Peoplebandingtogetherasaunifiedforce.;
C、Peoplebandingtogetherasademocraticparty.;
D、PeoplebandingtogethertocelebratethepublicationofLeavesofGrass.