Who is really the "Discount Broker"?

Let me pose this scenerio to you:

Broker A opens a company and decides that she is going to have the following office policy:
1) Every agent will charge 3% of the sales price for every listing.
2) On every Buyer's Brokerage agreement she will seek payment from the listing agent but if they do not pay she will charge the buyer 3% of the sales price as her commission.
The market is tough and competition is high but she sticks to her policy.

Broker B opens a company and decides that she is going to have the following office policy:
1) Every listing agent will charge 4% of the sales price if the property is sold in-house" and 7% for every property that is co-oped.
2) On every Buyer's Brokerage agreement she will seek payment from the listing agent but if they do not pay she will charge the buyer 3% of the sales price as her commission.
The market is tough and competiton is high but she sticks to her policy.

Broker C opens a company and decides that she is going to have the following office policy:
1) Every agent will charge 6% of the sales price for every listing.
2) On every Buyer's Brokerage agreement she will seek payment from the listing agent but if they do not pay she will charge the buyer 3% of the sales price as her commission.
The market is tough so she allows her agent to set the commissions and to get the listing they sometimes drop to 5%.

Which one is REALLY the discount Broker?