The Following Table Shows Per-Day Production Data of Rice and T-Shirts

The following table shows per-day production data of rice and T-shirts for two countries,Cambria and Bodoni.Based on the table,it can be said that the opportunity cost of 1 ton of rice in Cambria is _____.​ ​
Table 17.1
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A) 3 T-shirts
B) 10 T-shirts
C) 20 T-shirts
D) 30 T-shirts
E) 40 T-shirts