De Saussure labelled language as a

The correct option is Profusion of signs.

Ferdinand de Saussure, the Swiss linguist widely regarded as one of the founders of modern linguistics and semiology (semiotics), conceptualized language fundamentally as a system of signs. Under his structuralist framework, language is not merely a collection of words that label pre-existing things, but an organized system where meaning is produced through relationships.
Here is a step-by-step breakdown of why this designation is central to Saussure's theory:

1. The Structure of the Sign:
Saussure defined a linguistic sign as a two-part entity consisting of:
- The signifier (the physical sound-image or written word).
- The signified (the mental concept or idea associated with the signifier).
These two elements are intimately linked, like two sides of a single sheet of paper.

2. A Network of Differences:
In Saussure's view, no sign has meaning in isolation. Meaning is generated differentially, meaning a sign is defined by what it is not in relation to other signs within the language system. Because language is a vast, interconnected, and dynamic network constructed entirely of these signifying units, it is described as a profusion of signs.

Therefore, Saussure's definition of language rests on it being a structured and abundant system of signs, making "Profusion of signs" the correct description.