Question

At Bletchley Park, the main site in Britain where Enigma codes were deciphered, six thousand messages were decoded every day by a staff of ten thousand men and women. Many of the messages were inconsequential, but more than a few were critical to the outcome of the war.

Which is the best summary of this paragraph?

At Bletchley Park, thousands of people worked hard to help the British and Allied troops during the war.
At Bletchley Park, the ten thousand people on the staff figured out over six thousand codes, some of which were very important to the war effort.
Ten thousand people worked at Bletchley Park, but some of the codes they solved were inconsequential to the war effort.
Six thousand codes were figured out at Bletchley Park, including some that had importance in regard to the war.

Answer 1

At Bletchley Park, the ten thousand people on the staff figured out over six thousand codes, some of which were very important to the war effort.

This choice best captures the key facts: the staff size, the large number of messages decoded, and that some were critical to the war.