Let f left-parenthesis x right-parenthesis equals 2 x squared plus x minus 3 and g left-parenthesis x right-parenthesis equals x minus 1. Perform the indicated operation, then find the domain. left-parenthesis f minus g right-parenthesis left-parenthesis x right-parenthesis A. x squared minus 4; domain: positive real numbers B. 2 x squared minus 4; domain: all real numbers C. x squared minus 4; domain: all real numbers D. 2 x squared minus 2; domain: all real numbers