In YEAR 1, the price of gadgets is $2, while the price of the single variable input used is $28.

POSSIBLE ANSWERS:

1) 

all of the production plans are feasible

2) 

plans (a), (b) and (c) are feasible, plan (d) is NOT feasible

3) 

plans (a), (b) and (d) are feasible, plan (c) is NOT feasible

4) 

plans (a), (c) and (d) are feasible, plan (b) is NOT feasible

5) 

plans (b), (c) and (d) are feasible, plan (a) is NOT feasible

6) 

two of the plans are feasible, two are NOT feasible

7) 

only plan (a) is feasible, plans (b) , (c) and (d) are NOT feasible

8) 

only plan (b) is feasible, plans (a) , (c) and (d) are NOT feasible

9) 

only plan (c) is feasible, plans (a) , (b) and (d) are NOT feasible

10) 

only plan (d) is feasible, plans (a) , (b) and (c) are NOT feasible

11) 

NONE of the production plans are feasible

Could you please show me how to tell feasibility for this question? Thanks.