Final answer:
The correct revision of the sentence is Option A: Balboa discovered the Pacific Ocean and then claimed it for the king of Spain, as it is the most concise and structurally sound option without unnecessary repetition.
Step-by-step explanation:
The sentence 'Balboa discovered the Pacific Ocean and then he claimed it for the king of Spain.' should be rewritten for clarity and conciseness. The correct rewritten form is:
Option A: Balboa discovered the Pacific Ocean and then claimed it for the king of Spain.
This option eliminates the unnecessary repetition of the subject 'he' following the conjunction 'and.' It is concise and maintains the original meaning of the sentence. Official titles such as 'king' when used with a name like 'the King of Spain' should be capitalized. However, when the title is used as a general noun as in 'the king of Spain,' it is not typically capitalized.