The correct option is C Cr
The symbols of most of the elements are taken from the first letter of the element's name in English.
Elements like carbon, cobalt, etc. have "C" as their first letter. If the first letter of the elements are the same, then use the first two letters of the element’s name.
If the first two letters of the elements are the same, then use the next prominent letter for writing the symbol. For chromium, "r" is the next prominent letter, so "Cr" is the chemical symbol.