GraphQl mutation error as "Cannot read property '_id' of undefined"

Question

I want to create a mutation. So my code snipped like that:

Mutation: {
        createSocial: async (_, { social }) => {

            console.log(social) ===========================================>>>>>>> undefined

            const db = await mongo.then(d => d.db('social'))
            const { insertedId } = await db.collection('social-medias').insertOne(social)
            return insertedId.toString()
        }
    }

And my query like that:

module.exports = gql`
    extend type Query {
        social(id: String!): SocialMedia
    }
    extend type Mutation{
        createSocial(social: SocialMediaInput) : Boolean
    }
`

finally my type like that:

input FacebookProviderInput{
    user_id: String
    access_token: String
}
type FacebookProvider {
    user_id: String!
    access_token: String!
}
input SocialMediaProviderInput{
    facebook: FacebookProviderInput
}
type SocialMediaProvider {
    facebook: FacebookProvider
}
input SocialMediaInput{
    provider: SocialMediaProviderInput
}
type SocialMedia {
    merchant_id: String!
    provider: SocialMediaProvider
}

With this code snippeds I send a request as:

But I getting error as you see. Why Im getting this error? How can solve this error. Please Help!