Answer:
b. & Puihaha
Explanation:
PHP variables are supposed to start with a $ sign.
Other rules followed by PHP variables are:
Starting character in variable name (after $) must be letter or _.
Other characters in variable names can be letters,numbers or _.
a. $_Puihaha
c. $Pui_haha
d. $Puihaha
satisfy these rules.
Whereas , b. & Puihaha does not satisfy as it starts with '&'. Moreover it also contains an invalid space character in the variable.
Graphic design has as its goal the communication of some specific message to a group of people.
Specific is your answer.
Excel is mainly graphing information, or putting it into tables- organizing data. So I'd say D.