3. The term inferior goods refers to what kind of goods?
A. goods that consumers demand more of when their incomes increase
B. two goods that are bought and used together
C. goods that consumers demand less of when their incomes increase
D. goods used in place of one another

C.goods that consumers demand less of when their incomes increase

Explanation:

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.