Retrieve option set text in CRM 2011 server side

This method was taken from Guru Prasad's Blog. Here we can find several methods based on your needs that you can use to achieve the needed result. Thank you Guru!

I'll share one of the methods that I used in my code using metadata service:

public static string GetoptionsetText(string entityName, string attributeName, int optionSetValue, IOrganizationService service)

        {
            string AttributeName = attributeName;
            string EntityLogicalName = entityName;
            RetrieveEntityRequest retrieveDetails = new RetrieveEntityRequest
            {
                EntityFilters = EntityFilters.Attributes,
                LogicalName = EntityLogicalName
            };
            RetrieveEntityResponse retrieveEntityResponseObj = (RetrieveEntityResponse)service.Execute(retrieveDetails);
            Microsoft.Xrm.Sdk.Metadata.EntityMetadata metadata = retrieveEntityResponseObj.EntityMetadata;
            Microsoft.Xrm.Sdk.Metadata.PicklistAttributeMetadata picklistMetadata = metadata.Attributes.FirstOrDefault(attribute => String.Equals
            (attribute.LogicalName, attributeName, StringComparison.OrdinalIgnoreCase)) as Microsoft.Xrm.Sdk.Metadata.PicklistAttributeMetadata;
            Microsoft.Xrm.Sdk.Metadata.OptionSetMetadata options = picklistMetadata.OptionSet;
            IList<OptionMetadata> OptionsList = (from o in options.Options
                                                 where o.Value.Value == optionSetValue
                                                 select o).ToList();
            string optionsetLabel = (OptionsList.First()).Label.UserLocalizedLabel.Label;
            return optionsetLabel;
        }