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 _____.
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Table 19.1
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$$\begin{array} { | c | c | c | c | } \hline { \text { Cambria } } & & { \text { Bodoni } } \\\hline \begin{array} { c } \text { Tons of rice per } \\\text { day }\end{array} & \text { T-shirts per day } & \begin{array} { c } \text { Tons of rice per } \\\text { day }\end{array} & \text { T-shirts per day } \\\hline 20 & 0 & 100 & 0 \\\hline 18 & 80 & 90 & 100 \\\hline 16 & 160 & 80 & 200 \\\hline 14 & 240 & 70 & 300 \\\hline 12 & 320 & 60 & 400 \\\hline 10 & 400 & 50 & 500 \\\hline 8 & 480 & 40 & 600 \\\hline 6 & 560 & 30 & 700 \\\hline 4 & 640 & 20 & 800 \\\hline 2 & 720 & 10 & 900 \\\hline 0 & 800 & 0 & 1,000 \\\hline\end{array}$$

A) 3 T-shirts
B) 10 T-shirts
C) 20 T-shirts
D) 30 T-shirts
E) 40 T-shirts