Synopsis :

A. Index

B. Mixture

C. Summary

D. Puzzle

Answer: Option C

Solution(By Examveda Team)

Index :an indicator, sign, or measure of something.
Mixture :a substance made by mixing other substances together.
Puzzle :cause (someone) to feel confused because they cannot understand or make sense of something.
Summary :a brief statement or account of the main points of something.
Synopsis :a brief summary or general survey of something.

Synonym of Synopsis is Summary.