(a)    Number of monochloroderivatives of cyclohexane.

(b)    How many 1, 2 shifts are possible in the rearrangement of carbocation

(c)    Number of α-H atoms in most stable carbocation among the following    

(d)    Number of stereocentres in the following compound.

Write answer of part (a), (b), (c) & (d) in the same order and present the four digit number as answer. For example : If all these answer are 9 then fill 9999.