Given the following decision table:

Which of the following test cases and expected results is VALID?
Which of the following is MOST characteristic of specification based (black-box) techniques?
Given the following fragment of code, how many tests are required for 100% decision coverage?
discount = 0
order_quantity=0
real order_quantity
if order_quantity >=20 then
discount = 0.05
if order_quantity >=100 then
discount = 0.1
end_if
end_if
Exhibit:

Which of the items displayed in the exhibit are characteristic of regression testing.