You have been appointed as the network administrator in Well Brew Ltd$.$ The WPS $($Wi$-$Fi Protected Setup$)$ in the office is user$-$friendly, but not very secure$.$ A recent problem highlighted that the PIN can be easily cracked through a brute force attack, which means simply trying numerous possible character combinations to find the correct combination. Which of the following attacks have you most likely encountered?

a$.$ WPA attack

b$.$ War driving

c$.$ WPS attack

d$.$ War chalking