c. language is the correct answer.
"A system of symbols structured by grammar and syntax common to a community of people" is language.
Language is a way that allows us to communicate, exchange our thoughts and ideas and it also helps to interact with each other and develop bonds, economic relations, and social relations.
The symbols applied in language can involve communication and writing to express our thoughts and feelings.
Language is a technique or style of human communication either spoken or written consisting of use of words in a structured and conventional way. It allows for exchange of thoughts and communication.
The other options there are perception and communication which are wrong. Communication can be done without a system of symbols structured by grammar, while perception is the ability or process of understanding something.
Perception is being able to understand and notice, that is perceive, while communication can occur even without a system of symbols or without any structure.