List the top vendor in terms of purchase dollar amount for the period between $1/1/2021$ and $11/30/2021.$ This query investigates the possibility of vendor bribery. List a count of the number of distinct vendors each inventory item was purchased from for the year $2021.$ With the assumptionthat inventory purchases are spread out among vendors evenly, this helps identify items where the number of vendors purchased from is too low potentially indicating favoring certain vendors. Hint: note that there are only $8$ vendors in the Vendor table. How many different kinds of inventory items were purchased during October $2021?$