Answer:
Ricardo should specialize in the production of computer because it has a lower opportunity cost.
Smith should specialize in the production of smart phone because of the lower opportunity cost.
Explanation:
The opportunity cost for Smith to produce 1 computer is 4 smartphone(s).
1:4
The opportunity cost for Ricardo to produce 1 computer is 2 smartphone(s).
1:2
The opportunity cost for Smith to produce 1 smartphone is 1/4 of a computer(s).
1:1/4
The opportunity cost for Ricardo to produce 1 smartphone is 1/2of a computer(s).
1:1/2
Ricardo should specialize in the production of computer because it has a lower opportunity cost.
Smith should specialize in the production of smart phone because of the lower opportunity cost.