Mongo - Efficient way of deleting and returning particular projection after all

I have a such a model of MyEntity(s).

[{
    id: "1",
    ar:
    [{
        aId: "a",
        option: "option-4"
    }, {
        aId: "b",
        option: "option-2"
    }, {
        aId: "c",
        option: "option-3"
    }]
}, {
    id: "2",
    ar:
    [{
        aId: "d",
        option: "option-5"
    }, {
        aId: "e",
        option: "option-6"
    }, {
        aId: "f",
        option: "option-7"
    }]
}]

As a result of delete operation I want to remove entries from 'ar' array which satisfies aId and options and in the return I want to have IdWithOptions:

[{
    id: "1",
    options: [2, 3]
}, {
    id: "2",
    options: [5, 6]
}]

The only thing, which I don't like, is that I'm using o => options.Contains(o.option) two times, and I don't knnow how to avoid that.

public async Task<IEnumerable<IdWithOptions>> DeletePaths(string aId, IEnumerable<string> options)
{
    var builder = new FilterDefinitionBuilder<MyEntity>();
    var filter = builder.ElemMatch(m => m.ar, o => o.aId.Equals(aId));
    IEnumerable<IdWithOptions> idWithOptions = this.collection
        .Find(filter).ToEnumerable()
        .Select(o => new IdWithOptions()
        {
            id = o.id,
            options = o.ar.Where(o => options.Contains(o.option)).Select(p => p.option)
        })
        .ToList();

    var pull = new UpdateDefinitionBuilder<MyEntity>()
        .PullFilter(m => m.ar, o => options.Contains(o.option));
    await this.collection.UpdateManyAsync(filter, pull);

    return idWithOptions;
}