Considering that we travelled right across the country, the bus ticket was surprisingly reasonable.  

A Because we were able to move right through the country, the price of the bus ticket didn't bother us.

B The ticket for the bus, which took us from one side of the country to the other, was the cheapest that we could find.

C The most reasonable way to go right across the country was by bus, so we bought ourselves a ticket.

D As the bus brought us right across the country, we found the price of the ticket to be cheaper than its value to us.