Identify each of the following business combinations as being vertical$-$backward, vertical$-$forward, horizontal, product extension, market extension, or conglomerate:

a$.$ An inboard marine engine manufacturer is acquired by an outboard engine manufacturer.

b$.$ A cosmetics manufacturer acquires a mail order movie rentalcompany.

d$.$ A computer manufacturer acquires a chip manufacturer.

e$.$ The Walt Disney Company acquires a broad casting company.

f$.$ A California$-$based electric utility acquires a Colorado electric utility company.