If α and β are the zeroes of the quadratic polynomial f(x) = x² – 5x + k such that α-β=1, then value of k is:

(a) 6

(b) 0

(c) 1

(d) –1

If α and β are the zeroes of the quadratic polynomial f(x)=x²–p(x+1)–c, then (α+1)(β+1) is equal to:

(a) 1 + c

(b) 1 – c

(c) c – 1

(d) 2 + c 

If α and β are the zeroes of the quadratic polynomial f(x) = x² – x – 4, then the value of \(\frac{1}{\alpha}+\frac{1}{\beta}-\alpha \beta\) is:

(a) \(\frac{15}{4}\)

(b) \(-\frac{15}{4}\)                                    

(c) 4

(d) 15