Read the following passage and choose the best answer (A, B, C or D) to each question.

A recent survey of crime statistics shows that we are all more likely to be burgled now than 20 years ago and the police advise everyone to take a few simple precautions to protect their homes. The first fact is that burglars and other intruders prefer easy opportunities, like a house which is very obviously empty. This is much less of a challenge than an occupied house, and one which is well-protected. A burglar will wonder if it is worth the bother. There are some general tips on how to avoid your home becoming another crime statistic. Avoid leaving signs that your house is empty. When you have to go out, leave at least one light on as well as a radio or television, and do not leave any curtains wide open. The sight of your latest music centre or computer is enough to tempt any burglar. Never leave a spare key in a convenient hiding place. The first place a burglar will look is under the doormat or in a flower pot and even somewhere more 'imaginative' could soon be uncovered by the intruder. It is much safer to leave a key with a neighbour you can trust. But if your house is in a quiet, desolate area be aware that this will be a burglar's dream, so deter any potential criminal from approaching your house by fitting security lights to the outside of your house. But what could happen if, in spite of the aforementioned precautions, a burglar or intruder has decided to target your home. Windows are usually the first point of entry for many intruders. Downstairs windows provide easy access while upstairs windows can be reached with a ladder or by climbing up the drainpipe. Before going to bed you should double-check that all windows and shutters are locked. No matter how small your windows may be, it is surprising what a narrow gap a determined burglar can manage to get through. For extra security, fit window locks to the inside of the window. What about entry via doors? Your back door and patio doors, which are easily forced open, should have top quality security locks fitted. Even though this is expensive it will be money well spent. Install a burglar alarm if you can afford it as another line of defense against intruders. A sobering fact is that not all intruders have to break and enter into a property. Why go to the trouble of breaking in if you can just knock and be invited in? Beware of bogus officials or workmen and, particularly if you are elderly, fit a chain and an eye hole so you can scrutinise callers at your leisure. When you do have callers never let anybody into your home unless you are absolutely sure they are genuine. Ask to see an identity card, for example. If you are in the frightening position of waking in the middle of the night and think you can hear an intruder, then on no account should you approach the intruder. It is far better to telephone the police and wait for help.

A. mathematics B. biology C. experiment D. philosophy