An example of a density-independent factor would be
a) blight (a mold disease) in a wheat field
b) record cold temperatures that kill subtropical plants in northern florida
c) suitable nest sites for a flock of kirtland's warblers
d) wolves that prey on elk in yellowstone national park
e) a specialist searching for the one species of plant that is its food

(B) record cold temperatures that kill subtropical plants in northern Florida

Explanation:

This is any influence that has a negative impacts on a population’s fertility or mortality rate irrespective of the population density.

Examples of density dependent factors are physical factors of the environments, temperature, pollution,natural disasters, and atmospherics oxygen levels

the answer to you question is   jet streams