-  61 = a + (12 - 1) 5
a = 6
Series 6, 11, 16

• An arithmetic progression (AP) is a sequence of numbers, in which each term is obtained by adding a fixed number, called the common difference (d), to the preceding term.
• The common difference (d) of an AP is the difference between any two consecutive terms.
• The nth term of an AP is represented by tn = a + (n−1)d, where the first term of the AP is a and d is the common difference.
• In the given problem, the 12th term is 61, and the common difference is 5. Therefore, the equation to find the 12th term is t12 = a + (12−1)5.
• Solving the equation gives us a = 6.
• Therefore, the series is 6, 11, 16, 21, 26, 31, 36, 41, 46, 51, 56, 61.
Therefore, the correct answer is Option A.