This is not supported. The stimulus doesn’t talk directly about when ants forage. We also can’t draw a conclusion from temperatures, because we only know about Sahara afternoon temperatures. When and where is it cool enough for pheromones? We have no clue.

This is not supported. The stimulus doesn’t indicate if any ants live in the Sahara at all, much less that most non-pheromone-using ants do.

This is strongly supported. We know that ants can’t use pheromones to navigate during most Sahara afternoons. This means that if any ants only forage during Sahara afternoons, they generally can’t—so don’t—navigate using pheromones.

This is not supported. The author never suggests how ants might navigate other than by using pheromones. We have no idea if it’s a different substance or some other method altogether.

This is not supported. It might seem like not being able to use pheromones in high temperatures would lead to less-efficient foraging, but we don’t know about other ways ants could navigate. Maybe there are equally or more-efficient methods than pheromones.