Table schema:
CREATE TABLE table_name_98 (pick VARCHAR, college VARCHAR, round VARCHAR, position VARCHAR, overall VARCHAR)

Question: What is the total number of Pick, when Position is OT, when Overall is greater than 91, when Round is greater than 21, and when College is Mississippi?
SQL: SELECT COUNT(pick) FROM table_name_98 WHERE position = "ot" AND overall > 91 AND round > 21 AND college = "mississippi"