Goods 1 and 2 are perfect complements, and a consumer always consumes them in the ratio of 2 units of good 2 per unit of good 1. If a consumer has an income of $720 and if the price of good 2 changes from $8 to $9, while the price of good 1 stays at $1, then the income effect of the price change:

-is 8 times as strong as the substitution effect.

-is 9 times as strong as the substitution effect.

-is exactly twice as strong as the substitution effect.

-accounts for the entire change in demand.

-does not change demand for good 1.