The actual sentence-
Some Republicans concede that climate change caused by human activity is real,
but nonetheless
fear — as some Democrats — the president’s policies destroy jobs for miners and hurt the broader economy.
Clause 1 - climate change caused by human activity is real
Clause 2 - the president’s policies destroy jobs.
Republicans concede that <clause 1> but fear <clause 2> in incorrect .
Here, the clause 2 should be preceded by THAT.
We can eliminate choices
A and B. Some Republicans concede as some democrats -- Incorrect comparison of "concede (verb)" with "democrats(noun)"
Some Republicans concede as DO some democrats -- correct. The action (concede) of republicans and democrats are compared.
We can further eliminate choice
C.Left with D and E.
(D) as do some Democrats — that the president’s policies will destroy jobs for miners and hurt the broader economy
(E) as do some Democrats — that the president’s policies will
destroy jobs for miners,
and hurting the broader economy as well
Parallelism issue in E . Destroy
|| hurting. Eliminate
E.
Thus,
D is the answer.