You are given a math word problem and you are supposed to make use of mathematical concepts like probability, combinatorics, linear equations, sequences/series, or simple operators like addition, subtraction, division, or multiplication to answer the given question. Choose the best option from the 5 given options and report that option.

Question: The cost price of a radio is Rs.1500 and it was sold for Rs.1230, find the loss %?

 Option A: 18%

 Option B: 19%

 Option C: 28%

 Option D: 38%

 Option E: 16%
Option A

Question: A train speeds past a pole in 15 sec and a platform 140 m long in 25 sec, its length is?

 Option A: 210

 Option B: 150

 Option C: 160

 Option D: 170

 Option E: 180
Option A

Question: If A(k)=(k+1)^k, and k=1, what is the value of A(A(A(k-1)))?

 Option A: 0

 Option B: 2

 Option C: 1

 Option D: 6

 Option E: 9

Option C