Answer:
The sans-culottes' identity as rooted in their socioeconomic status
Explanation:
The Sans-culottes were the poor in the then French government who revolted against the leadership because of their poor living conditions. A Marxist historian would study the effects of capitalism on the economy and social welfare of a state.
A Marxist historian arguing against the contention that the Sans-culottes were emerging into the working class will cite the fact that the identity of the sans-culottes was as a result of their place in the society as well as their economic status.