A bank tells a potential borrower that the mortgage interest rate is $3\mathrm{.}20\%.$ The borrower does not lock in this interest rate, and by the time the borrower is ready to buy a house, the rate has increased by $32$ basis points. What is the percentage $($not percentage point$)$ change in the interest rate?

a$.+10\%$

b$.+3\mathrm{.}2\%$

c$.+0\mathrm{.}32\%$

d$.-0\mathrm{.}32\%$