Who wanna play smash or pass?

Here’s the first one let me send the next page of the passage

By the late 1930s, how were u. s. officials beginning to view japanese policies of expansion? a. they attempted to join forces with japan so as to increase u. s. territory. b. they warned them to stop expansionist actions or face potential u. s. intervention. c. they sent representatives to japan to work out territorial rights in a diplomatic fashion. d. they became fearful of their military power

What does the term “escalation” refer to?