Business-style leather shoes. Briefcase or portfolio, no backpack. If employers tell you that the dress is business casual, then you should use the following dress code. If you're not sure, ask. Ties are optional, with wool or cotton sweaters, trousers, and loafers with dark, coordinated trouser socks being fairly common.
Higher heels are no longer as popular as they used to be.
Flat leather shoes with dark, coordinating trouser socks are appropriate.