To solve this question, we can figure out what each of the words mean (specifically) and then put them into the blank and see which one fits best.
Burning is normally regarding a fire, one very hot and bright.
Sultry means that the air is hot and humid.
Blazing means burn fiercely or brightly.
Thermogenic means tending to produce heat, and it is commonly referring to drugs.
The best word that fits is sultry, so we know that the answer is B, sultry.
