Consider the Following Diagram, and Then Answer the Question Below

Consider the following diagram, and then answer the question below.

-What best explains the "bumps" seen in the seen in the CO₂ concentrations on the graph above?

A) changes in plant growth that result in less CO₂ being absorbed during the dormant season
B) a cyclic pattern in the eruption of volcanoes, causing more CO₂ to be released each spring
C) greater amounts of CO₂ released by the burning of fossil fuels for heat during the winter
D) higher levels of traffic producing more CO₂ during the summer travel season