Answer: D. about 400 meters
Step-by-step explanation:
Firstly, we need to know 1 feet is equivalent to 0.3048 meters:
[tex]1 ft=0.3048 m[/tex]
Then, we can make the conversion from 1300 feet to meters:
[tex]1300 ft \frac{0.3048 m}{1 ft}=396.24 m[/tex]
Hence, Mount St. Helens lost [tex]396.24 m[/tex], which can be approximated to [tex]400 m[/tex].
This means the correct option is D.