Isolde was entering a contest to win a two$-$night stay at a cabin in Gatlinburg, Tennessee from a local radio station's website. The form asked for Isolde's name, address, and birthdate. At the bottom, she noticed a box that was checked saying she agreed to receive communication emails from the radio station. She unchecked the box before submitting the information. This action is an example of $q,$

a$.$ double opt$-$in

b$.$ opt$-$out

c$.$ confirmed opt$-$in

d$.$ opt$-$in