Imagine an essay built around this claim:

The process known as hydraulic fracturing is touted by the
natural gas industry as safe, but environmentalists do not
agree with this assessment.
Which of the following claim restatements would be most appropriate to start
the conclusion paragraph?
A. Natural gas companies are able to drill into previously untapped
natural gas reserves to extract gas from shale rock in a process
known as fracking.
B. Although extracting natural gas from shale in a process called
fracking is believed to be safe by industry experts, scientists beg
to differ with them.
C. Chemicals that are used in the fracking process have been known
to leak into aquifers that supply drinking water for residents who
live near fracking sites.
D. Debate runs high over the safety of hydraulic fracking, but so far,
environmentalists are losing out to the deep pockets of investors
in gas energy.

The most appropriate restatement to start the conclusion paragraph would be:

B. Although extracting natural gas from shale in a process called fracking is believed to be safe by industry experts, scientists beg to differ with them.