Which statement best describes the viewpoint the author expresses about intelligence? firsthand intelligence is more effective than secondhand intelligence. it was not necessary to gather firsthand intelligence from east berlin. firsthand intelligence is intelligence taken from decrypted, or decoded, messages. the us had not been able to plant a spy in east berlin to gain intelligence.

A viewpoint is an opinion statement. When answering the question we should first eliminate all fact statements. This eliminates the last two options as those are statements of fact. The answer you're looking for could be A or B. It depends on the passage this statement is about. If the passage focuses the entire time on East Berlin and how other forms of intelligence besides firsthand intelligence was effective then B is your answer.  
However, A is also a possibility. If the entire passage discusses the benefits of firsthand intelligence over secondhand intelligence then this is the answer.

The answer is A. Firsthand intelligence is more effective then second hand intelligence

A. an is indefinite article