Splitting Binary Stars As seen from Earth, the red dwarfs Kruger $60 \mathrm{A}$ and $\mathrm{Kruger} 60 \mathrm{B}$ form a binary star system with an angular separation of 2.5 arc seconds. What is the smallest diameter telescope that could theoretically resolve these stars using $550-\mathrm{nm}$ light? $\left(\right.$ Note: 1 arc $\left.\sec =1 / 3600^{\circ}\right)$