Which two reasons could be possible explanations for this?

A team that works on a big project uses npm to deal with projects dependencies.

A developer added a dependency does not get downloaded when they execute npm install.

Which two reasons could be possible explanations for this? Choose 2 answers
A . The developer missed the option –add when adding the dependency.
B . The developer added the dependency as a dev dependency, and NODE_ENVIs set to production.
C . The developer missed the option –save when adding the dependency.
D . The developer added the dependency as a dev dependency, and NODE_ENV is set to production.

Answer: B,C,D