A student argues: “The sequence 6,10,14,18,… is NOT an arithmetic progression because the ratio of consecutive terms is not constant.” Which option best explains the error in the student’s reasoning?
(a) He mistakenly thought that an arithmetic progression is defined by a constant sum of consecutive terms.
(b) He has confused the condition for a geometric progression with that for an arithmetic progression.
(c) He believed that an AP must have a common ratio of 1 between consecutive terms.
(d) He assumed that the constant interval in an AP is measured between alternate terms, not consecutive ones.