Mike and Sandy are two woodworkers who both make tables and chairs. In one month, Mike can make 4 tables or 20 chairs, where Sandy can make 6 tables or 18 chairs. Given this, we know that the opportunity cost of 1 chair is
A -1/5 table for Mike and 1/3 table for Sandy
B- 1/5 table for Mike and 3 tables for Sandy
C- 5 tables for Mike and 1/3 table for Sandy
D- 5 tables for Mike and 3 tables for Sandy