The correct answer is B.
Income elasticity of demand is a measure of how responsive the demand for a good or service is to changes in income. It is calculated by dividing the percentage change in the quantity demanded of a good or service by the percentage change in income.
In this case, the income elasticity of demand for rice is 0.5. This means that for every 10% increase in income, the demand for rice will increase by 5%.
A positive income elasticity of demand indicates that the good or service is a normal good. This means that as income increases, people will demand more of the good or service.
A negative income elasticity of demand indicates that the good or service is an inferior good. This means that as income increases, people will demand less of the good or service.
An income elasticity of demand of 0 indicates that the good or service is a necessity. This means that people will demand the good or service regardless of their income.
In the case of rice, it is a normal good. This is because rice is a staple food that is consumed by people of all income levels. As income increases, people will demand more rice.
The other options are incorrect because they do not represent the correct relationship between income and demand for rice.