在金融詞彙里,lock down,open a franchise是什麼意思

題目：

在金融詞彙里,lock down,open a franchise是什麼意思
One example refers to Jeff ’s biggest day in the market when he made $50,000.$50,000 in one day!People were flocking to the Block Trading headquarters in Houston and dropping $25,000 just for the right to lock down a city for opening a franchise at some point in the future.Block Trading is no longer around,but there are some lessons to be learned from those early days.
整段話是這樣的.
dropping $25,000 just for the right to lock down a city for opening a franchise at some point in the future.這句話特別不理解.
那這整句話里是什麼意思呢

解答：

LOCK DOWN的意思是「鎖定下來」
OPEN A FRANCHISE的意思是「開一家特許經營店」