Step 1: Know what TIR measures.
In the 3 to 14 micron window, a sensor is not catching sunlight bounced off a surface. It is catching heat that the surface itself is giving off. The amount of this heat depends on how hot the surface is and how well it radiates, which is its emissivity.
Step 2: Go through the options one by one.
Forest fire: a burning area is much hotter than its surroundings, so it stands out clearly as a bright spot in TIR imagery. This is how satellites flag active fires. This option works.
Rainfall pattern: rain is normally tracked with microwave sensors that see through cloud tops, or with visible imagery of cloud shape. TIR can only see how cold the top of a cloud is, which is not the same as measuring rain on the ground. This option does not fit.
Ground surface temperature: this is the single most direct product of TIR remote sensing. The radiance recorded is converted into temperature using the physics of blackbody radiation. This option works.
Emissivity: since different surface materials radiate heat at slightly different rates for their temperature, multi-band TIR instruments can separate out temperature and emissivity together. This option works.
Step 3: Collect the working options.
Fire detection, surface temperature, and emissivity are the three quantities that TIR data gives directly. Rainfall stays outside this list.
\[ \boxed{\text{Forest fire, Ground surface temperature, Emissivity}} \]