To get the number of different types of awards that have been won, you should use the formula COUNTD({Award}). This formula will return the count of distinct values in the Award field, which are the different types of awards that have been won.
The other options are not correct for this scenario. COVAR({Award}) is not a valid function in Tableau. MAX({Award}) will return the maximum value in the Award field, which may not be a type of award. INDEX() will return the index or rank of each row in a partition, which is not related to the types of awards. Reference: https://help.tableau.com/current/pro/desktop/en-us/functions_functions_aggregate.htm#COUNTD https://help.tableau.com/current/pro/desktop/en-us/functions_functions_tablecalculation.htm#INDEX