In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Example Input: Problem: a lady starts from p towards q and realizes that at a point r , if he walks 50 km further he will be at a point s , which is as far away from r as it is from q . what is the distance between p and q if the distance between p and r is half the distance from r to q ? ( assume that p , q , r and s are all on the same straight line ) 
Options: a ) 150 km , b ) 200 km , c ) 250 km , d ) 125 km , e ) 155 km
Example Output: a

Example Input: Problem: the distance between 2 cities a and b is 1000 km . a train starts from a at 11 a . m . and travels towards b at 100 km / hr . another starts from b at 12 p . m . and travels towards a at 150 km / hr . at what time do they meet ? 
Options: a ) 11 am . , b ) 12 p . m . , c ) 3 pm . , d ) 4 p . m . , e ) 1 p . m .
Example Output: d

Example Input: Problem: a train 150 m long crosses a platform 100 m long in 10 sec ; find the speed of the train ? 
Options: a ) 100 , b ) 70 , c ) 95 , d ) 90 , e ) 85
Example Output:
d