Step 1: Tractor tyres must be inflated to a suitable pressure for proper traction, steering, and load carrying.
Step 2: Front wheel tyres generally require higher inflation pressure than rear tyres because they are smaller and assist in steering.
Step 3: The usual range of inflation pressure for front wheel tractor tyres is:
\[
1.5-2.5\ \text{kg/cm}^2
\]
Step 4: Therefore, the correct answer is:
\[
\boxed{1.5-2.5\ \text{kg/cm}^2}
\]