In which of the following pairs the gaseous species diffuse through a porous plug along with the same rate of diffusion

If two or more gases have same molecular weight then their rate of diffusion to be same.

Molar mass of NO=14+16=30

${\mathrm{C}}_2{\mathrm{H}}_6=2\times 12+6\times 1=30$

Both NO and ${\mathrm{C}}_2{\mathrm{H}}_6$have same molar mass. So their rate of diffusion is also same