Read the Following Argument and Then Answer Multiple Choice Items

Multiple Choice

Read the following argument and then answer multiple choice items.
The lakeshore condominium project will threaten the ecology of the Lake Superior shoreline. The plan calls for widening Lakeshore Drive to four lanes, putting in six highrise buildings, and building a four-foot wall around the complex. Look what happened when a similar project was built in Duluth-water fowl lost their nesting places and the grasses that hold the shoreline were uprooted by construction equipment. When there is a major construction project along a shoreline, the plant and animal life are harmed.
-"When there is a major construction project along a shoreline, the plant and animal life are harmed," functions as which part of this unit of argument?

A) grounds
B) backing
C) warrant
D) claim