C.
More importantly, is attitude. (Also, worth noting, I carry IWB with a CTAC and a tucked in shirt when I do conceal. It can be done easily, and very well.) However, nobody mugs the man who is a man. If you walk with a purpose, show signs of alertness, and have an aura around you that commands respect, muggers will move on to easier prey.
Having worked in terrible parts of town, I have found that attitude is the key. I have seen guys who liked like giant apes cowed because they feared, and much smaller guys, and even a few women, stare down the same thugs. It is almost 100% attitude. If a mugger thinks they will be mugged, they will be looking elsewhere for work. Like NYC as previously mentioned.