Treatment of one stereoisomer of 2-iodo-3-phenylbutane

Here is my question.  I am working through this and some other problems, and want to compare what I do against what someone who knows a lot more than me on this subject, does.  

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PROBLEM:

Treatment of one stereoisomer of (2 ?, 3R)-2-iodo-3-phenylbutane with base, yields (E)-2-phenylbutene.

a)  Determine which enantiomer of 2-iodo-3-phenylbutene gives the E product (2R, 3R or 2S, 3R), and explain clearly (using unambiguous diagrams) why that is the case.

b)  Assign that enantiomer as either R or S at carbon 2.