If it is rational, it has a terminating decimal or a repeated decimal number (ex. 56, or 1.25, or 3.666...)
If it is irrational, it is an ongoing number with no pattern (ex. 3.14159265... Which is pi)
Answer is number 2
F(3)= (3-1)^2+ 3(3)=4+9= 13 so the first option is wrong
F(-2)= (-2-1)^2+ 3(-2)= 9-6=3 third options is wrong
F(-15)= (-15-1)^2 +3(-15)= 256-45= 211 fourth option is wrong