In the springtime, many people begin sneezing and suffering from allergies. Which is the most likely cause of these allergies?

The correct answer is - pollens.

Explanation:

During the springtime of the year, Pollination is common among plants and there are many plants that use air or wind as the medium for spreading the pollens. Such weeds, grass, and trees use this type of wind-pollination.

These are the most common allergens during this time that leads to sneezing and suffering from allergic reactions. Pollens are too heavy to be airborne for a longer time or they are inhaled from the air and lead to allergic reactions.