(a)  Total number of optical isomers of tartaric acid.
(b)  Total number of optical isomers of 1,2-Dichloro cyclohexane.
(c)  Total number of stereoisomers of But-2-ene.
(d)  Total number of stereoisomers of 1,3 dichloro cyclobutane. 

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