♥ $$\times$$ ☺ $$=$$ ♦  Since ☺ is an even number,~♦ must also be an even number.  ♦ $$-\textasciitilde7$$ is the only option to given an odd answer because even $$-$$ odd $$=$$ odd. 
♥ $$\times$$ ☺ $$=$$ ♦  ☺ is an even number.  Which of the following gives an odd answer? 
a: ♦ $$-\textasciitilde7$$ 
b: ☺ $$+$$ ♦ 
c: ☺ $$\times$$ ☺ 
d: ♦ $$\times$$~♦ 