Hello. You did not inform what work this question refers to, but through the context of the question and the name of the character, we can consider that you are referring to the theater play "Anne Frank" that reproduces Anne Frank's account of the time that she went into hiding with her family before being deported to a Nazi concentration camp.
Although Anne and her entire family had been in hiding for three years, they had Austrian friends who helped them have supplies necessary for food and hygiene. One of those friends was Mr. Kraler. However, one day he brought a news that caused concern to all the residents of the hideout, which was called a secret annex that was in a commercial building. Mr. Kraler claimed that a warehouse worker could have discovered the Frank family's hiding place and was blackmailing Mr. Kraler so that he would not divulge what he knew. This worried the Franks a lot and is connected to Act 1, as it shows that all the care and preparation of the family to not be discovered, in Act 1, may have been in vain.
"Dynamic" would be the best option from the list in terms of a word that best describes the English language. This is because the English language, like many other languages, is always evolving and changing.
