Which of the Following Can Be Said to Be True

Which of the following can be said to be true about the learning principle?

A) As long as students have their basic facts and procedures memorized,they do not have to understand how the mathematics works.
B) Due to technology,it is no longer necessary for students to practice computational skills.
C) Learning is strongly enhanced when students are encouraged to make and test their own mathematical conjectures.
D) To build confidence,students should be taught to focus on their own mathematical ideas and not the thinking of others.