Examples of sentences with the structure (not) as... as:
His face is not as round as Tom´s.
Her eyes are not as big as mine.
His nose is as turned-up as his mother´s.
Mary´s hair is as curly as her friend´s.
The policeman is as angry as the car driver.
The TV host is not as bored as the audience.
The children are as happy as their grandparents.
The correct answer is D.
Stream of conscious narration is an example of experimentation in American modernism. The other techniques were commonly used long before the advent of modernism and would not be examples of experimentation.