"The OPEC oil embargo" was the reason of the oil crisis during the 1970s among the choices given in the question. The correct option among all the options that are given in the question is the third option or option "C". I hope the answer has actually come to your desired help.
There are about 7,643,402,521
people in the world. However there are people being born and dying every few seconds. So as of right now there is 7.74 billion people! :)
I'm glad I could assist you! Have a great day!
Your answer is a, and c. i hope this has helped, as i have had the same question earlier plus i have the same text book to, so i hope this has helped.