If I had to choose one, I'd go for b. However, a and d are also correct.
What does your book say?
4. Why should you summarize?
a) Primary sources are hard to understand without summary.
b) Because summarizing is more effective than paraphrasing.
c) none of these is correct
d) So your paper doesn’t turn into a string of quotations.
3 answers
Research article in a journal about the impact of climate change is a _____________ resource.
Travel guide book is a _____________ resource.