Consider the following sequence 3, 6, 9, 12. (a) Classify the sequence as arithmetic, geometric, Fibonacci, or none of these. O arithmetic geometric O Fibonacci O none of these (b) If arithmetic, give d; if geometric, give r; if Fibonacci, give the first two terms. (If Fibonaco, enter your answers as a comma-separated list. 2 none of these, enter NONE (c) Supply the next term