If you wanted to add a special effect $($such as "show", "hide" or "spin"$)$ to an HTML user$-$interface element $($such as a "submit" button$),$ what jQuery libraries $(.$js files$)$ are needed?

a$.$ jquery.js and jquery$-$ui$.$min.js

$($the jquery core library and the jquery user$-$interface plug$-$in$)$

b$.$ jquery.js and jquery.validate.js

$($the jquery core library and the jquery validation plug$-$in$)$

c$.$ jquery.js

$($Just the jquery core library$)$

d$.$ jquery$-$ui$.$min.js

$($just the jquery user$-$interface plug$-$in$)$