Answer:
b) two gases
Step-by-step explanation:
A homogenous mixture is one in which the various components in the mixture are uniformly distributed such that they appear as a single phase.
In contrast, in a heterogenous mixture there is a non-uniform distribution of the different components which results in the formation of visibly different phases.
Based on the given options, a mixture of gases can only be homogenous since particles in the gas phase move quickly relative to the liquid and solid phase and can spread out into a uniform (homogenous) composition.