Answer :
I think the correct answer from the choices listed above is the second option. The fireworks exhibition had awesome effects. The word effects seems to be the right word to complete the thought of the statement. Hope this answers the question. Have a nice day.
The correct answer is effects.
An effect is a noun derived from the verb to affect. The exhibition showed nice EFFECTS, but it AFFECTED the audience - the first word is a noun, and the second one a verb.
A defect is something bad, something lacking, missing, so that's wrong here. In order for show to be correct, there has to be an article - The fireworks exhibition had AN awesome show.