Lisa and Robert have taken the same number of photos on their school trip. Lisa has taken 3 times as many photos as Claire and Robert has taken 12 more photos than Claire. How many photos has Claire taken?  Select the correct option:
A) 6 B) 8 C) 10 D) 12 E) 14

Rationale: "explanation : l = r l = 3 c r = c + 12 we can substitute r for l in the second equation : r = 3 c . if r is equal to both 3 c and c + 12 , we can say 3 c = c + 12 , and solve for c . 3 c = c + 12 2 c = 12 c = 6 answer : ( a )"
Answer: A