Question 769522
Please help.  

Rationalize the denominator of 2/{{{root(3,a-1)}}}
A.  2{{{root(3,(a-1)^2)}}}/a-1
B.  8/a-1
C.  2({{{root(3,a)}}}+1)
D.  4/a-1
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Let a = 28, see if any of them fit.