Store, Model, ViewModel: what's the correct way?

HI!

I have some doubts with extjs 5.1.0

What is the correct way to use store, model and viewmodel

A) this one:

Model:

Code:

Ext.define('App.model.MyModel', {
    extend: 'Ext.data.Model',


    fields: ['id', 'name', 'email', 'address'],


    proxy: {
        type: 'ajax',
        api: {
            create  : '/contacts/create',
            read    : '/contacts/read',
            update  : '/contacts/update',
            destroy : '/contacts/destroy'
        },
        reader: {
            type: 'json',
            rootProperty: 'contacts',
            totalProperty: 'total'
        }
    }
});

STORE:

ISSUE: we still need a store like this?

Code:

Ext.define('App.store.MyStore', {
    extend: 'Ext.data.Store',
    alias: 'store.mystore',

    config: {
        model: 'App.model.MyModel'
    }
});

VIEWMODEL:

Code:

Ext.define('App.view.model.MyViewModel', {
    extend: 'Ext.app.ViewModel',
    alias: 'viewmodel.myviewmodel',

    stores: {
        contacts: {
            type: 'mystore',


            autoLoad: {
                page: 1,
                start: 0,
                limit: 10
            },
            pageSize: 10
        }
    }
});

B ) or can do so only:

VIEWMODEL:

Code:

Ext.define('App.view.model.MyViewModel', {
    extend: 'Ext.app.ViewModel',
    alias: 'viewmodel.myviewmodel',

    stores: {
        contacts: {
            type: 'mystore',

            fields: ['id', 'name', 'email', 'address'],
              
            autoLoad: {
                page: 1,
                start: 0,
                limit: 10
            },
            pageSize: 10,


            proxy: {
                type: 'ajax',
                api: {
                    create  : '/contacts/create',
                    read    : '/contacts/read',
                    update  : '/contacts/update',
                    destroy : '/contacts/destroy'
                },
                reader: {
                    type: 'json',
                    rootProperty: 'contacts',
                    totalProperty: 'total'
                }
            }
        }
    }
});

C) or is there a more correct way? Which One?

Thanks in advance.

Store, Model, ViewModel: what's the correct way?