Eurostar launches an investigation after passengers were stranded for five hours and had to smash windows to v_______ carriages. 旅客被困五小时不得不打破车窗使车厢通风，欧洲之星对此展开了调查。

All of the following are travel agents’ suggestions to Eurostar except（） A: marketing its service so it can be more competitive than airlines. B: increasing the frequency of daily journey. C: updating its image and doing more commercial deals. D: providing flexible tickets to travel agents.