In which one of the following situations should we be most concerned about the possibility of subtractive bilingualism?

a) A child growing up in a multilingual household with supportive parents who encourage language development.
b) An immigrant child attending a school where their native language is not supported or respected.
c) A language learner who voluntarily participates in language classes outside of their regular curriculum.
d) A community where bilingualism is celebrated and actively promoted through cultural events and language programs.