Answer: a)

b) income elasticity = 0.521
Explanation:
Since we have given that
Demand function is stated as

Here, P stands for price.
stands for price of alternative good
Y stands for income of consumers
1) we have given that
P=10, PA= 12 and Y=1000
So, Q becomes

Price elasticity of demand would be

Hence,

2) P=10, PA= 12 and Y=1000
So, Income elasticity of demand would be

Hence, income elasticity = 0.521