18) Which MATLAB command is used to clear command window in 18) A) open B) new D) clc C) clean 19) Which MATLAB A) clear 19) is used to clear all defined variable in MATLAB workspace? B) zeros command C) delete D) eye 20) if the following MATLAB command executes, what would the printed result? 20) A-5 B-A+5 B=B+2; D) 5 A) 0 B) 9 C) 12