C. Sigmund Freud is the answer
A - Although he denies them, Dr. Vasequez faced several scandals last year.
A complex sentences must have both a dependent clasuse (although he denies them) and an independent clause (Dr. Vasquez faced several scandals last year.
Options B and D are compound sentences (two independent clauses) and option C is a simple sentence.
In the choices above, the correct answer that corresponds to the statement is letter A, there is one right source for a certain information. It is because in doing a research, there is always a source in order for your information to be true or for it to have a support. Researches are in need to bear in mind that there are always a source for each information.
Explanation:
answer-
It allows the boys to share their talents for the benefit of everyone.
I dont know never read the book