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: A train covers a distance of 12 km in 10 min. If it takes 10 sec to pass a telegraph post, then the length of the train is?

 Option A: 100

 Option B: 110

 Option C: 200

 Option D: 130

 Option E: 140
Option C

Question: The toll for crossing a certain bridge is $0.75 each crossing. Drivers who frequently use the bridge may instead purchase a sticker each month for $13 and then pay only $0.10 each crossing during that month. If a particular driver will cross the bridge twice on each of x days next month and will not cross the bridge on any other day, what is the least value of x for which this driver can save money by using the sticker?

 Option A: 12

 Option B: 15

 Option C: 16

 Option D: 28

 Option E: 29
Option A

Question: The mass of 1 cubic meter of a substance is 200 kilograms under certain conditions. What is the volume, in cubic centimeters, of 1 gram of this substance under these conditions? (1 kilogram = 1,000 grams and 1 cubic meter = 1,000,000 cubic centimeters)

 Option A: 0.8

 Option B: 1.25

 Option C: 8.0

 Option D: 12.5

 Option E: 5

Option E