In the past six months, Luke's take$-$home income increased from $$4,000$ per month to $$5,000$ per month $($an increase of $25\%).$ While on vacation, Luke encouraged his wife to buy some new jewelry. Normally, his wife would only buy one item of jewelry while on vacation. However, this time she purchased four items of jewelry $($an increase of $300\%).$

The income elasticity calculated using the formula for income elasticity is $\_\_\_\_\_\_\_\_\_\_$ and the jewelry items are a $\_\_\_\_\_\_\_\_\_\_$ good.

a$.)$

$12\mathrm{.}0$; normal

b$.)$

$0\mathrm{.}12$; normal

c$.)$

$6\mathrm{.}0$; luxury

d$.)$

$12\mathrm{.}0$; luxury