All of these are correct.

Topological sorting is crucial in scheduling tasks

Topological sorting of a directed acyclic graph (DAG) is a linear ordering of vertices such that for every directed edge uv, vertex u comes before v in the ordering.

Topological sorting can be used resolving symbol dependencies in compilers

In one of the topological sorting algorithm, DFS is used for node exporation from each unvisited node,

One of the topological sorting algorithm starts by calculating the in-degree (number of incoming edges) for each vertex.