${?}_{{?}_{{?}_{?}}{?}_{{?}_{?}}{?}_{{?}_{?}}{?}_{{?}_{?}}{?}_{{?}_{?}}{?}_{{?}_{?}}\text{i}\text{n}\text{v}\text{o}\text{l}\text{v}\text{e}\text{s}\text{t}\text{h}\text{e}\text{c}\text{o}\text{m}\text{b}\text{i}\text{n}\text{a}\text{t}\text{i}\text{o}\text{n}of\text{f}\text{i}\text{r}\text{m}\text{s}in\text{u}\text{n}\text{r}\text{e}\text{l}\text{a}\text{t}\text{e}\text{d}businesses.}$

Question $18$Select one:

$a.$

Horizontal merger

$b.$

Congeneric merger

$c.$

Conglomerate merger

$d.$

Vertical merger