12) C

Customer 1 was not refunded any money because the train arrived only 1 minute late.

Customer 2 was not refunded any money.

Customer 3 would have been refunded $6 since their trains was more than 20 minutes late.

Customer 4 would have been refunded $4 since their trains was more than 10 minutes late but less than 20 minutes late.

Customer 5 would not have been refunded any money.

Customer 6 would not have been refunded any money.

Customer 7 would not have been refunded any money.

Customer 8 would not have been refunded any money.

Customer 9 would have been refunded $6 since their trains was more than 20 minutes late.

Customer 10 would have been refunded $6 since their trains was more than 20 minutes late.

Total money refunded by company = 6 + 4 + 6 + 6 = $22

So the answer is C.