Answer:
C. major political parties ignore vital issues
Step-by-step explanation:
Currently, there's only 2 major political parties in United States. Democrats and Republicans. Any party other than those two often considered as "third-party".
One Example a big third party movement is the Green party.
This party gained momentum in 2001 due to the raising concern of Climate Change in Untied States. But, none of the major political party make active legislations to address the problem.