The pollen allergies are common during the spring and the fall, as during this time, the plants release their pollen grains for fertilization. These pollens can cause allergic reactions in some individuals. This allergic reaction is the result of the release of a certain chemical known as 'histamine'. The release of histamine in the body is triggered by the presence of the pollen grains in the respiratory system, and it causes reactions like water eyes and runny nose.
Hence, the correct answer is 'Option B'.
