Select the most appropriate option that can substitute the bold segment in the given sentence.

Not only is my brother intelligent though hard working too.

I. x² – 10x + 21 = 0

II. y² + 11y + 28 = 0

I. 2y² - 35y + 132 = 0

II. 2x² - 31x + 110 = 0

I. 24x² - 58x + 23 = 0

II. 20y² + 24y – 65 = 0

I. √(74x-250 )– x=15

II. √(3y²-37y+18)+ 2y=18

I. 2y²- 37y + 143 = 0

II. 2x²+ 15x – 143 = 0

I. 2x² + 12x + 18 = 0

II. 3y² + 13y + 12 = 0

I. x² + 16x + 63 = 0

II. y² + 2y - 15 = 0

A and B are the roots of equation x² - 13x + k = 0. If A - B = 5, what is the value of k?

I. (x^13/5 ÷7) = 5488 ÷ x^7/5

I. 117x² + 250x + 117 = 0

II. 54y² -123y + 65 = 0