Answer: 2. Although the presentation was extremely long, it outlined the research, analyzed the data, and provided clear recommendations that will be useful in the future.
Explanation:
Parallel Sentences are constructed when you used the same grammatical form across the entire sentence. This way the sentence is balanced and easier to read.
For example, Sophia likes reading, hiking and watching television. As opposed to, Sophia likes reading, hiking and watch Television. The watch in the sentence is not using the grammatical form that is the present participle which is present in most of the sentence.
The correct sentence above therefore is the second one.
It uses the same form throughout the sentence by putting it in past tense.
