Read the following passage and determine which sentence could be added to further support the central idea.

West Virginia is aptly nicknamed the Mountain State. It has an average elevation of 1,500 feet above sea level, which makes it the highest of any state east of the Mississippi River. The Appalachian and Allegheny Mountains are a part of West Virginia landscape, and many outdoor activities are centered around the mountains. Everything from rock climbing, to skiing, to hiking are all centered around these beautiful mountains.

a) Montana is a state that also has beautiful mountains.

b) The New River Gorge Bridge is a popular tourist attraction.

c) West Virginia's tallest mountain is Spruce Knob.

d) West Virginia broke away from Virginia to become its own state in 1863.

c) West Virginia's tallest mountain is Spruce Knob.

The sentence that could be added to further support the central idea is:

c) West Virginia's tallest mountain is Spruce Knob.

To determine which sentence could be added to further support the central idea of the passage, we need to identify what the central idea is. The central idea is that West Virginia is aptly nicknamed the Mountain State because of its high elevation and the presence of the Appalachian and Allegheny Mountains.

Now, let's evaluate the options:

a) Montana is a state that also has beautiful mountains.
This sentence does mention another state with beautiful mountains, but it does not directly support the central idea of the passage, which is focused on West Virginia.

b) The New River Gorge Bridge is a popular tourist attraction.
This sentence provides additional information about a specific tourist attraction in West Virginia. While it does not directly mention the mountains, it supports the central idea by highlighting a popular attraction that may be connected to the mountainous landscape.

c) West Virginia's tallest mountain is Spruce Knob.
This sentence directly supports the central idea by providing factual information about West Virginia's mountains. It adds to the discussion of the landscape and elevations mentioned earlier in the passage.

d) West Virginia broke away from Virginia to become its own state in 1863.
This sentence provides historical information about West Virginia's separation from Virginia, but it does not directly support the central idea of the passage, which is focused on the mountainous landscape.

Based on the evaluation, the sentence that could be added to further support the central idea is:
c) West Virginia's tallest mountain is Spruce Knob.