The Red Scare was a time in the US when Americans were worried and determined to protect the US from Communist influence and protect democracy and capitalism.
The correct answer should be D. energy.
He was one of the first abstract painters and there wasn't much pathos there, not many emotional things. Lines and shapes were often use but they weren't the aim of it, rather just a part of the form. He portrayed energy flowing, moving, changing, things like that were fascinating to him.