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.

Q: Question: A train running at the speed of 60 km/hr crosses a pole in 21 seconds. What is the length of the train?

 Option A: 350 m

 Option B: 278 m

 Option C: 876 m

 Option D: 150 m

 Option E: 267 m

A: Option A
****
Q: Question: In the xy-plane, line q passes through point (3,-2) and intersect perpendicularly with line n that passes through points (0,3) and (3,5). What is the equation of line q?

 Option A: 3x+2y-5=0

 Option B: 3x+2y+5=0

 Option C: 2x-3y-12=0

 Option D: 2x+3y=0

 Option E: 4x+3y-6=0

A: Option A
****
Q: Question: The cost of 4 bags and 12 purses is Rs.1520, what is the cost of 10 bags and 30 purses?

 Option A: Rs.3600

 Option B: Rs.3500

 Option C: Rs.3800

 Option D: Rs.3900

 Option E: None of these

A:
Option C
****