Question

Which landform represents the boundary between the land and an ocan or lake

Answer 1

A) a coastline represents the boundary between land and the ocean or a lake.

Answer 2

First of all, a coast is where land ends and the sea/lake starts.

Therefore, the coastline, is the "border", or as you said it, the boundary between the continent and a sea or in some cases a lake.

Answer:

$\boxed{\bf~A - Coastline}$

Hope it helped,

BioTeacher101