Consider two stationary spherical pure water droplets of diameters $d_{1}$ and $2d_{1}$. $CO_{2}$ diffuses into the droplets from the surroundings. If the rate of diffusion of $CO_{2}$ into the smaller droplet is $W_{1} \text{ mol } s^{-1}$, the rate of diffusion of $CO_{2}$ into the larger droplet is

1. $2W_{1}$
2. $4W_{1}$
3. $W_{1}$
4. $0.5W_{1}$