In the past eight months, Raquel's income increased from $1,000 per month to $1,200 per month (an increase of 20%). Raquel usually made 16 cheese sandwiches in a month. With her new salary, she now only makes 10 sandwiches per month (a decrease of 37.5%). The income elasticity calculated using the formula for income elasticity is __________ and the cheese sandwiches are __________ good. a.) -0.4; an inferior b.) 1.9; a luxury c.) -1.875; an inferior d.) 0.5; a normal