Options :

1. Inertial mass is a measure of difficulty of accelerating a body by an external force whereas the gravitational mass is relevant in determining the gravitational force on it by an external mass

2. That the gravitational mass and inertial mass are equal is an experimental result

3. That the acceleration due to gravity on earth is the same for all bodies is due to the equality of gravitational mass and inertial mass

4. Gravitational mass of a particle like proton can depend on the presence of neighouring heavy objects but the inertial mass cannot