A is the answer. B has a 'plural verb' and a singular subject, as does C. D has a plural subject and 'singular verb'
It makes you feel and think a certain way about something. If optimism is a mental attitude, than it benefits the world by if you give a bad attitude towards polluting the earth other people can realize that and actually fight to stop that cause as one.
The thesis shouldn’t include 8-10 sentences. True
