Read the following passage about the truth behind body language and mark the letter A, B, C, or D to indicate the correct option that best fits each of the numbered blanks from 18 to 22.

Words convey the messages that we want others to hear, but our bodies may tell a different story. Whether we express our problems to our colleagues with a hunched back and sad, downcast eyes, or our enthusiasm for life with a cheerful spring in our step, our bodies are constantly sending out messages. And understanding these clues that we unavoidably offer each other (18) _______.
'People vary enormously in their ability to detect non-verbal cues,' says Dr Peter Bull, psychologist at the University of York. 'Those who tend to be good at detecting emotions and getting the timing right when raising tricky subjects are usually picking up others’ moods through these non-verbal clues,' he says. 'But (19) _______.'
The ability to manipulate your own body language is suggested as an essential skill when it comes to making a good impression. ‘Aiming to communicate interest and enthusiasm at an interview, (20) _______,' says Bull.’ General facial cues suggesting alertness, while showing that you are listening, can help. And your tone of voice should be lively and interested.' Though we can portray a false emotion to a certain extent, few can fool a skilled observer, (21) _______.
Decoding the real message can be a tricky business and becomes even more complicated when different cultures begin to mix. But whether that’s the culture of a country or company, (22) _______, including the unspoken messages that accompany the words.
(Adapted from Ready for First)