How To Get Base Currency in CRM 2011,2013,2015

QueryExpression query1 = new QueryExpression("transactioncurrency");

        query1.ColumnSet = new ColumnSet(new string[1] { "isocurrencycode" });

        QueryExpression query2 = query1;

        query2.AddLink("organization", "transactioncurrencyid", "basecurrencyid", JoinOperator.Inner);

        Entity entity = CrmServiceHelper.Service.RetrieveMultiple(query2).Entities[0];

        if (entity == null)

            return;

        string BaseCurrency = entity["isocurrencycode"].ToString().ToUpper();

CRM 2011:You do not have the necessary permissions to change the domain logon name for this user

https://astutecrm.wordpress.com/2012/08/27/crm-2011-unable-to-change-domain-logon-name-access-denied-error/