Briefly define the following terms.
a) Tariff escalation
b) Optimal tariff rate
c) Ad valorem tariff equivalent
d) Voluntary export restraint (VER)
e) Terms of trade effect (of subsidy)
f) Harmonized System (HS) of commodity Classification
g) Common external tariff
h) Dumping
i) Quota Rent
j) Offspring
k) Offshore outsourcing