Some Republicans concede that climate change caused by human activity

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.