Let `x,y,z` belong to `N` and `alpha, beta, gamma` be prime numbers. If `xyz=alpha^3beta^3gamma^2` Then number of positive integral solutions of equation `xyz=alpha^2 beta^3 gamma^2` = number of ways of distributing two alpha 's among three persons)(number of ways of distributing three beta's among three persons)(number of ways of distributing two gamma's among three persons) `=.^(3+2-1)C_2xx^(3+3-1)C_3xx^(3+2-1)C_2`, `= .^4C_2xx^5C_3xx^4C_2=6xx10xx6=360`. On the basis of above information answer the following question: If `a` is a factor of 60, then number of positive integral solutions of equation `xyz=a` is (A) 54 (B) 81 (C) 64 (D) 160