Find the name of bank branch that provided the greatest total amount of loans to customers with credit score is less than 100.
select t2.bname from loan as t1 join bank as t2 on t1.branch_id = t2.branch_id join customer as t3 on t1.cust_id = t3.cust_id where t3.credit_score < 100 group by t2.bname order by sum(t1.amount) desc limit 1