Task: Question Answering
Input (English): Question: Three pieces of timber 42 m, 49 m and 63 m long have to be divided into planks of the same length, What is the greatest possible length of each plank ?

 Option A: 7 m

 Option B: 14 m

 Option C: 42 m

 Option D: 63 m

 Option E: None of these
Output (English): Option A