Among the following ${132}^2,{87}^2,{72}^2$ and ${209}^2$ would have 1 at unit place

Last digit of 132 is 2 $\therefore 2^2=4$ last digit of ${132}^2$ =4

Last digit of 87 is 2 $\therefore 7^2=49$ last digit of ${87}^2$ =9

Last digit of 209 is 9 $\therefore 9^2=81$ last digit of ${209}^2$ =1

Last digit of 72 is 2 $\therefore 2^2=4$ last digit of ${72}^2$ =4