Examples, one with a comma and one without:
Shakespeare was born in Stratford and went on to write Hamlet.
Shakespeare was born in Stratford, later writing Hamlet
Williams employs a humorous and often sarcastic tone to communicate the complexity of representing her composite ethnic identity in a single dish.
Answer:
The Grapes of Wrath can be read as a proletarian novel, advocating social change by showing the unfair working conditions the migrants face when they reach California. The men who own the land there hold the power, and attempt to control supply and demand so that they can get away with paying poor wages.
D is your answer as the sentence is in present tense.