The correct option that expresses the given sentence in active voice is The member nations formulated a new policy for peace and tolerance in the Universal Council meeting yesterday.

The other options are incorrect because:

• A new policy for peace and tolerance was formulated by the member nations in the Universal Council meeting yesterday is in the passive voice.
• The member nations in the Universal Council meeting yesterday were formulated a new policy for peace and tolerance is grammatically incorrect. The verb "to formulate" is transitive, which means that it takes a direct object. However, the subject of the sentence is "the member nations," which is not a direct object.
• The member nations in the Universal Council meeting yesterday were formulating a new policy for peace and tolerance is in the present progressive tense, while the original sentence is in the simple past tense.
• A new policy formulated the member nations in the Universal Council meeting yesterday for peace and tolerance is grammatically incorrect. The subject of the sentence is "a new policy," which is not the one who formulated the policy.