Ten Students solved a total of 35 questions in a Global Math Olympiad. Each question was solved by exactly one student. There is at least one student who solved exactly one problem, at least one student who solved exactly two problems, and at least one student who solved exactly three problems. What is the minimum number of students who has/ have solved at least four problems?

• A.  1
• B.  2
• C.  6
• D.  5