Landscape photography had not yet been invented in medieval times.
This justifies what answer for what question? Q & A: 
Is the following statement true?
"Knights in Medieval England enjoyed Landscape photography."
no
Landscape photography had not yet been invented in medieval times.
This justifies what answer for what question? Q & A: 
user
Is the following statement true?
"Knights in Medieval England enjoyed Landscape photography."
no
assistant
Landscape photography had not yet been invented in medieval times.
This justifies what answer for what question? Q & A: 
Is the following statement true?
"Knights in Medieval England enjoyed Landscape photography."
no