Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions. 

     The British are particular about timings and being late is frowned upon, but being on time is a complicated matter because in some situations, being a few minutes early on others means being exactly on time and in some instances, it is completely acceptable to arrive 10 minutes to a few hours later than the stated time. This can be a minefield for someone who is new to the UK, so here are some basic rules that will help you get your timing right whatever the situation. 

     In formal meetings, such as job interviews, you should arrive at least five minutes before your meeting. This will give you time to compose yourself before your big meeting. In the UK, arriving late for a formal meeting is seen as unprofessional and will reflect badly on you. If you are running late, ring your host to let them know you will be late. On arrival, apologize sincerely and offer a reason for your lateness, such as you got lost or the train was delayed. It will help you redeem yourself. However, if you are late because you set off later than you should have, it's wise to keep that to yourself! 

     If you have been invited to a dinner party, you should arrive exactly on time as the host will have planned when they will serve the food. You will find that your host will serve their guests a pre-dinner drink, so that gives you a bit of wiggle room, but if you are running later than 10 minutes, you should ring your host and let them know how late you might be. That way they can decide whether to go ahead and serve the other guests. When you arrive you should offer the host and the other guests your apology for being late. 

(Source: https://www.oxfordinternationalenglish.com/) 

What is the author's main purpose in the passage?