The formula for the sum of n terms in an arithmetic progression is: S = n/2 * (2a + (n-1)d) Here, the common difference, d, is 8 and the first term, a, is 1. Substituting these into the formula, we get:
S = n/2 * (2*1 + 8(n - 1)) S = n + 4n² - 4n S = 4n² - 3n The answer is A.
