Honestly! I saw a ghost! I’m not ___ it up!
A having
B laughing   
C making  
D joking

5) Honestly! I saw a ghost! I’m not making it up!

C

Честно, я видел призрака! Я не выдумываю!

C making

Объяснение:

to make up - выдумывать

Honestly! I saw a ghost! I’m not making it up! (Честно! Я видел привидение! Я не выдумываю! )

1. i must brush my teeth. - anyone, most likely some disobedient child.

2. i have to brush my teeth. - a patient of dentist's, a human with diseased tooth.

3. i must tidy my room. - anyone, most likely some disobedient child.

4.i have to tidy my room. - anyone, probably a child.

5. i must take the medicine. - someone with easy form of illness.

6. i have to take the medicine. - most likely, a regular patient

explain (объяснять) – explanation (объяснение)

know(знать) – knowledge (знания)

inform(информировать) - information (информация)

progress(развиваться) – progress (развитие)