(d) The key word of the sentence is ‘thrive' which means ‘to grow, to develop'. Options (b) and (c) are out of context. Options (a) and (d) have close contexts. But, again option (a) weakens the argument as none of the words matches up with ‘thrive’. On the other hand, ‘contribution’ and ‘betterment’ get along with ‘thrive’. Hence, option (d) is correct.