Felipe and Gregory are given the arithmetic sequence - 1, 6, 13, ..... Gregory wrote the explicit definition an = - 1 + 7(n - 1) for the sequence. Felipe wrote the definition as an = 7n -8. Which one of them is correct? Explain. Choose the correct answer below. O A. Only Felipe's definition is correct because it is simplified. Gregory's definition is not simplified, so it cannot be correct. O B. Only Gregory's definition is correct. The explicit definition of an arithmetic sequence is an = a, + d(n - 1), and only Gregory's definition is of that form. O C. Both are correct. Gregory's definition can be simplified to get Felipe's definition. O D. Both are correct. Gregory's definition uses n = 1 for the first term whereas Felipe's definition uses n = 0 for the first term, but both definitions describe the given sequence.
