To stamp a mark on an envelope to show that the cost of posting it has been paid :
Apost
Bfrank
Ctax
Dfranc
Answer:
B. frank
Read Explanation:
Post = the official system used for sending and delivering letters, packages etc.
Tax = money that you have to pay to the government so that it can pay for public services.
Franc = the unit of money in Switzerland and several other countries.
