Complete the following passage by choosing A, B, C or D to fill in each blank.

In recent years, there has been a remarkable increase into happiness. The researchers have come up a number of factors which contribute to a definition of happiness.           First of all, there is, in some people, a moderate genetic predisposition to be happy, in other words, happiness (1)_______ in families. And happiness seems to correlate quite strongly with the main dimensions of personalities: extroverts are generally happier, neurotics are less so.           Second, people often report good social relations as a reason for their happiness. In particular, friends are a great (2)______ of joy, partly because of the agreeable things they do together, partly because of the way friends use positive non-verbal (3)______ such as caressing and touching, to affirm their friendship. Marriage and similar (4)______ relationships can also form the basis of lasting happiness.           Third, job satisfaction undoubtedly (5)______ overall satisfaction, and vice versa - perhaps this is why some people are happy in boring jobs: it (6)______ both ways. Job satisfaction is caused not only by the essential nature of the work, but (7)_____ by social interactions with co-workers. Unemployment, on the contrary, can be a serious cause of unhappiness.           Fourth, leisure is important because it is more under individual (8)______ than most other causes of happiness. Activities (9)_____ sport and music, and participation in voluntary work and social clubs of various kinds, can give great joy. This is partly because of the (10)______ themselves, but also because of the social support of other group members – it is very strong in the case of religious groups.

          First of all, there is, in some people, a moderate genetic predisposition to be happy, in other words, happiness (1)_______ in families.