Joan,__ Mr Smith is going to marry,is a textile worker.

Joan,__ Mr Smith is going to marry,is a textile worker.
Joan,__ Mr Smith is going to marry,is a textile worker.

Joan,__ Mr Smith is going to marry,is a textile worker.
whom/who都行,作后面marry的宾语,marry sb 与某人结婚

whom

Joan，whom/who__ Mr Smith is going to marry, is a textile worker.
whom/who作后面marry的宾语，marry sb 与某人结婚

whose