Answer:
B) Continually falling oil prices
Step-by-step explanation:
Oil prices did not fall continually from 1950-2007. In some periods the price of oil declined, but in most of those years, the price of oil rose. In fact, in the 1970s, oil prices rose so much, that it led to an energy crisis, and an economic recession, which especially hit the Carter and first Reagan administration.
Oil prices also have risen more than 400% since the start of the twentieth-first century, not only in nominal value, but also in real value (that is to say, accounting for inflation). I will attach a graph that shows these numbers in detail.