German Shipping Has Chartered a Ship to Tanzanian Freighters for Five

German Shipping has chartered a ship to Tanzanian Freighters for five years. In the second year of the contract, a severe crash in the charter price makes it more profitable for Tanzanian Freighters to breach the contract and find another charterer. To ensure the preservation of the contract, German Shipping agrees to reduce the charter price by £8,000 per month. By the end of the fifth year, the market still has not fully recovered to per crash levels. This only happens a full year later. Can German Shipping claim the difference in arrears, or is the renegotiation made in the second year enforceable?

A) GS cannot claim the difference in arrears; it is estopped from going back on its promise.
B) GS can claim the difference in arrears; promissory estoppel can only suspend rights, not extinguish them.
C) GS can claim the difference in arrears; promissory estoppel cannot create a new cause of action.