Stronger electrolytes have high degree of dissociation, which is followed by weak and non electrolytes respectively.
Here, H2SO4 is a strong electrolyte than compared to HCl . While HCOOH is a weak electrolyte.
On the other hand, glucose is a non electrolyte so it never dissociates.
Thus the correct order is H2SO4 > HCl > HCOOH > C6H12O6