The correct answer is negotiate.
The correct answer is (B) To negotiate, particularly over a small matter; to swap or trade by petty bargaining; to barter; to bargain; to haggle.
Dicker possibly comes from German decher (trading unit).
Examples of use:
- He dickered for a half hour over the quantity of gasoline to be included.
- With the main issues already resolved, they used their remaining time to dicker over a few minor aspects of the contract.