Final answer:
The correct answer is option a, which is 'pound & pond'. By removing 'U' from 'pound', a unit of British currency, we get 'pond', a term for a small body of water.
Step-by-step explanation:
The answer to the question "It's a British unit of currency; knock "U" out & you get a small body of water" is a. pound & pond. When you remove the letter "U" from pound, you are left with pond, which is a term for a small body of water. This interesting wordplay is a reminder of how fluid English vocabulary can be, and it also hints at the concept of exchange rates and their importance in international finance, as the British pound is a major currency that has seen significant fluctuations over time, particularly around events such as the Brexit vote.