Gore Co$.,$ Baker Bros., and Torrent Construction $($all cement companies in the area$)$ agreed that on three upcoming projects, Gore would bid lowest on the first project, Baker would submit the lowest bid on the second project, and Torrent would submit the lowest bid on the third project. In this way, they would each be assured of work for the upcoming season. This behavior:

a$.$

is legal and an acceptable practice in the construction industry to spread work more evenly.

b$.$

is an example of bid$-$rigging.

c$.$

is an example of price fixing.

d$.$

is an example of a horizantal cooperative agreement that is illegal.$$

e$.$

both $($b$)$ and $($d$).$