Which character other than gregor also undergoes a change in appearance
a. gregors father
b. gregors sister
c. gregors boss
d. gregors mother

A.Gregor's father

Gregor's father undergoes a transformation in his physical appearance just like his son. Mr. Samsa is forced to go back to work after Gregor's transformation, and ends up working as a bank messenger. He now stands very erect, dressed in a fancy, blue uniform. His eyes look brighter and his hair is combed. With the change in appearance, Mr. Samsa also gains a new sense of authority.

the present continuous is a verb tense which is mainly used to indicates that an action is in progress at the moment of speaking.  

it is formed using: person + verb to be (am/is/are) +verb + - ing form  

example: i am studying at this moment .

in addition, the present continuous is also used in order to express things that will or will not happen in the near future.

example: i am having dinner with some friends tonight.

the speaker sometimes   uses it   to express that an action is repeated and it causes irritation on the part of the speaker

example: my sister is constantly complaining about everything.

a, overstatement is the answer