I would suggest saying, "I would make an excellent president because...." (List your reasonings). For "Helpful," you don't need to capitalize the first letter. Make sure you add in an "and helpful," since you're finishing off the reasons.
Canadente is spelled incorrectly. It should be "Candidate."
Lastly, I would suggest saying "have had experience...."
The word means peace or undisturbed.
Based on the given sentence above, the error that I can find is the incorrect use of the pronoun "their". Looking at the sentence, the subject is "One of your students", this means only one, and not all the students. Therefore, this should take a singular pronoun. So the correct sentence would be "One of your students left his or her book on the table." So the answer for this would be option A. Hope this helps.
