Why double qoute for some queries in the mongosh does not work?

When I execute the following query it does not return any results.
db.grades.find({“class_id”:431, “scores”: {"$elemMatch": {“score”:{"$gte":85} }} })

But if I written I following way, it just works, but why ?
db.grades.find({class_id:431, scores: { $elemMatch: {score:{$gte:99} }}}).pretty()

db.grades.find({class_id:431, scores: { $elemMatch: {score:{$gte:85} }}}).pretty()

Most likely because you cut-n-paste the query from an HTML page that is not marked down correctly. So you ended up with the new fancy quotes rather than real ascii double quotes.

Replace all fancy quotes like in “class_id” with "class_id".

See Formatting code and log snippets in posts