Pull value from object -> array -> object -> object

1

I have this following strtucture

{
  _id: ".....",
  a: {
    a1:".......",
    b: [
      b1: {
        b11: "......",
        b12: "......",
      },
      b2: {
        b21: "......",
        b22: "......",
        d: {},
      },
      c:{
        c1: {
          ......
        },
        d: {

        }
      }
    ]
  }
}

here I want to check if property d exists or not inside b, it may exists in multiple objects inside b, if exists pull the d object from record.

Note: There might be a chance that property d exists multiple times inside b1 and b2, In this case I want to remove it from all objects

I tried like

Coll.find({ ‘a.b’: { $elemMatch: { ‘c’: { d: { $exists: true } } } } })

but it is not returning anything although there are records, any help appreciated.

I want to pull that data from record too.

Thanks.
UPDATE

Coll.find({ 'a.b.c.d'{ $exists: true } })

that worked for me but still no idea how to use positional operator to pull the value from record