Task: Question Answering
Input (English): Problem: an equilateral triangle t 2 is formed by joining the mid points of the sides of another equilateral triangle t 1. a third equilateral triangle t 3 is formed by joining the mid - points of t 2 and this process is continued indefinitely. if each side of t 1 is 40 cm, find the sum of the perimeters of all the triangles.
Options: ['a. 180 cm', 'b. 220 cm', 'c. 240 cm', 'd. 270 cm', 'e. 300 cm']
Output (English): c