Steve's barking; The stock market has gone down because....( not enough information )

Watching (actually listening) to business news channels during the current down turn in the markets. Answers given, because the price oil has dropped the stock markets have taken a hit.
                           Because the down turn of the Chinese economy (down turn not collapse) American companies are hurt.
                             Because of the crash of oil prices counties such as Saudi Arabia have to cash in their stocks and bonds from their sovereign wealth fund in order to pay their welfare programs.
. (Good possibility).
                             Because foreign markets have fallen, investors who bought shares of stocks and bonds on margin, their calls have come in and those who owe must sell what they can to cover. (Good possibility)
                              Because the market has gone down individual owners on margin must sell, forcing the market to go down. (Good possibility)
                               Because large institutions don't want to show to much negative income they are in panic and selling.(possible)
                                Because banks lent money to oil companies that might not be able to pay back, therefore their stocks are taking a beating.
Now some or all these reason may be correct, but there isn't enough information to make a correct judgement as to why the markets are collapsing.
 This is just like several test that I've taken were one of the possible answers is not enough information to answer the question.