Fill in the blanks with the most appropriate option:
Each of the Girl Scouts______ a community project.

In a sentence, the verb is used according to person and number.
In the case of the following words, the verbs used will be singular:
Each, every/everyone, someone/somebody, none/ nobody, one, any, many a, more than one, etc.​​
For example:
Everyone are addicted to smartphones nowadays. (Incorrect)
Everyone is addicted to smartphones nowadays. (Correct)
As per the rule and example have given above, 'does' will be used in the blank part of the given question.
Correct Sentence: Each of the Girl Scouts does a community project.