Arsenal have managed to concede a total of 51 premier league goals this season. Much has been said about their defence this season by experts and fans. Shkodran Mustafi has been the one under most criticism this season as he made error after error. There is no doubt that Arsenal will be signing defenders this season. Arsenal are already looking to bid on defenders like William Saliba and Walter Kannemann. However, The Gunners still need experienced and world class defenders. So who else can Arsenal look for to bolster their defence?Centre BacksWith Arsenal looking to offload Shkodran Mustafi, they will need to fill in that place with a world class centre back. So here are some of the options Arsenal have.