What is the domain of the relation graphed below? (refer to photo) ((4th choice is domain: {x|- 1 <=x<=1}. }

answer:  

\boxed {\frac{1}{5}}  

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

solution-

60 *   \frac{1}{5}   = 12

90 * \frac{1}{5} = 18

75 * \frac{1}{5} = 15

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

hence, the answer would be \boxed {\frac{1}{5}}