A camera with a focal length of $20$ cm fitted in an aircraft is used for taking vertical aerial photographs of a terrain. The average elevation of the terrain is $1200 \: m$ above mean sea level (MSL). What is the height above MSL at which an aircraft must fly in order to get the aerial photographs at a scale of $1:8000$?
- $2600 \: m$
- $2800 \: m$
- $3000 \: m$
- $3200 \: m$