Concept: The question tests on applying the basics of Equation in a DS format
Solution:
St (1) Reduces to 2x – y = 1
=>2x = y + 1
If y = 1 then x=1 = y (Yes )
If y = 5 then x =3 (No)
Hence Insufficient
St (2) Reduces to x-y = 0
x = y
(Yes)
Thus sufficient.
Hence Option (b)