Concept:Use the formula for the nth term of an Arithmetic Progression: l=a+(n−1)d.Explanation:In the A.P. 2,−9,−20,…,−141, the first term is a=2.The common difference is d=T2−T1=−9−2=−11.Check: T3−T2=−20−(−9)=−11, so d=−11.The last term is l=−141.Substitute into l=a+(n−1)d:−141=2+(n−1)(−11)−141=2−11n+11−141=13−11n−141−13=−11n−154=−11nn=−11−154=14Therefore, the number of terms is 14.Answer:n=14, which is Option D.