Answers for "can we rollback data with delete"

can you rollback with delete clause

yes, since this DELETE clause is from DML, 
we can use ROLLBACK to recover the data.

can we rollback data with drop

No we can't rollback data by using DROP

can we rollback data that are deleted using DELETE clause?

yes, since this DELETE clause is from DML,
we can use ROLLBACK to recover the data.