The practice of a general contractor revealing one subcontractor's bid to a competitor to obtain a lower price is called:

Explanation

Bid shopping is using one subcontractor's quoted price to push the others lower after bids are in. Value engineering is redesigning to cut cost without giving up function, and is legitimate. A scope review compares what work each bid actually covers, to find gaps and overlaps. Prequalification screens a bidder's capacity and finances before bidding opens. Only the first uses someone else's number as leverage; it is widely viewed as unethical and is restricted on public works to protect competitive bidding.