A mayor of a major international city wants to commemorate the upcoming city anniversary by constructing monuments. A design competition is announced, and 15 different proposals for monuments make the shortlist, 9 of them of Avant-Garde architectural style and 6 of Dutch Baroque architectural style. Because of budget constraints, it is decided that exactly 4 different proposals will be chosen randomly to proceed to the construction phase. What is the probability that all 4 monuments constructed will be of the same architectural style?

• A. 4/9+4/6
• B. (9/4)(6/4)/(15 4)
• C. (9 4)+(6 4)/(15 4)
• D. 4/9×4/6
• E. 9!4!6!4!/ 15!4!