Here a is 1 Byte and b is 2 Byte.
Initially.
a = 240
b = 1.
a : 240 241 242 243 244 ...................................255 0 ( here will check for a == 0 , will return b).
b: 1 2 4 8 16 32768 65536.( this can't be represented in 16 bit because we represent up to 65535 only).
It will be like this.
1(one extra bit) 00000000 00000000 ( 16 bit)
so, the answer is 0.
