Final answer:
The senator is using the justification of cultural preservation to support their argument.
Step-by-step explanation:
The senator is using the justification of cultural preservation to support their argument in favor of the trade restriction on telephoto lenses. Cultural preservation refers to protecting and preserving a nation's cultural heritage and identity. By restricting trade on telephoto lenses, the senator believes that they are protecting an aspect of their nation's culture and identity that is important to them.