Why do the woman and man of the song "I Will Always Love You" have to break up?

A、Themanchedtedthewoman.
B、Beacausethewomanknowstheyarenotrightforeachotherandmustlethimgo
C、Becausethewomandoesnotlovehimanymore.
D、Becausetheirparentstotallydisagreewiththeirrelationship.