Complex HUman!

[gmat_perfect]

Complex human traits such as artistic talent or social skill are likely to be shaped by thousands, if not tens of thousands, of the 80,000 or so genes in the human genome.

(A) such as artistic talent or social skill are likely to be shaped by thousands, if not tens of thousands, of the 80,000 or so
(B) such as artistic talent or social skill are likely shaped by thousands, if not tens of thousands, of 80,000 or so of the
(C) such as artistic talent or social skill is likely to be shaped by thousands, if not tens of thousands, of 80,000 or so of the
(D) like artistic talent or social skill is likely to be shaped by thousands, if not tens of thousands, of the 80,000 or so
(E) like artistic talent or social skill are likely shaped by thousands, if not tens of thousands, of the 80,000 or so

[spoiler]OA: A[/spoiler]

[reply2spg]

Took 1 minute, but got it wrong. IMO it is B but OA says A.

I kicked A out becuase of the redundancy. Why do we need 'are' and 'to be'?

Can somebody explain the meaning of 'if not tens of thousands, of 80,000 or so of the'?

Complex human traits such as artistic talent or social skill are likely to be shaped by thousands, if not tens of thousands, of the 80,000 or so genes in the human genome.

(A) such as artistic talent or social skill are likely to be shaped by thousands, if not tens of thousands, of the 80,000 or so
(B) such as artistic talent or social skill are likely shaped by thousands, if not tens of thousands, of 80,000 or so of the
(C) such as artistic talent or social skill is likely to be shaped by thousands, if not tens of thousands, of 80,000 or so of the
(D) like artistic talent or social skill is likely to be shaped by thousands, if not tens of thousands, of the 80,000 or so
(E) like artistic talent or social skill are likely shaped by thousands, if not tens of thousands, of the 80,000 or so

[spoiler]OA: A[/spoiler]

[indiantiger]

To me in B the following did not make sense :
"or so of the"