A primary source is preferable to a secondary source when .
A.
creating original research
B.
finding a collection of sources and accounts
C.
looking for a critique of others’ work
D.
interpreting other sources

B. Finding a collection of sources and accounts

This is because that’s what a primary source usually is- I dunno like a diary entry or a photograph or a letter or something. When looking for a collection of sources (primary sources are usually from that moment in history) and accounts (most of which primary accounts are) primary sources are super valuable. I think.