Which of the Following Is True

Which of the following is true?
I.The easier it is to find substitutes for a good,the more price elastic the demand for the good is.
II.The demand for a good is more price elastic the smaller the proportion of income spent on it.
III.If demand is price elastic,lowering the price leads to a decrease in total revenue.

A) Only I
B) Only II
C) Only III
D) I and II
E) I and III