Answer:
c. interesting.
Step-by-step explanation:
The use of synonyms can help you make your reading more interesting because it gives yout audience the opportunity to learn and to read new different words that weren´t in their vocabulary prior to reading your texts, using the same words over and over is tiring for those who read you, that´s why every writer needs to have a wide lexic and know a lot of synonyms to express widely different ideas.