What does the sign indicate?
A)Caution; intersection ahead.
B)Electronic toll or dynamic toll.Correct
C)No passing without stopping.
The sign in the question indicates that vehicles travelling in a lane marked in this way may make payment with the electronic toll system, but not compulsorily; they may also use other means of payment.
If the sign is mandatory (photo 1), we must compulsorily make the payment with the electronic toll system and we cannot use other means.
The «no passing without stopping» sign in answer c) would be the one in photo 2.