What Primarily Makes It Difficult to Observe the Process of Star

Multiple Choice

What primarily makes it difficult to observe the process of star formation?

A) Star formation occurs in dusty regions.
B) Forming stars have low luminosities.
C) Forming stars do not shine at any wavelength until they become T Tauri stars.
D) The star formation process happens so quickly.
E) Forming stars are too small to be seen.