Dropdown List to return a unique value

Question

Please help me with my workbook as Iam novice to Excel.

I have 2 sheets, "STOCKS" and "ORDERLIST" .....I want to automate in Allocation Column the email address of the client matching the criteria of Product_Name,Size and Gender. its should return the email address as unique value, is drop down list possible? as it will facilitate me to choose whom to send. whatever is possible please help me with this formulae.

Thanks

Files below:

Workbook One Drive

I tried to formulate matching two tables and returning the unique value matching both criteria. I tried to get the result from the other table if the both tables has common vlaue.