Under the given conditions, the only way is to embed the video with an object
element:
<object data=vodka.mp4 width=300 height=150>
See the <a href=vodka.mp4>video of our hamster</a>.
</object>
Browser support is limited, and even on supporting browsers, the user may be prompted for a permission to run a plug-in. So the idea of disallowing video
is odd, but I guess this is a school project, where such misguided requirements are imposed on formal and not-well-informed basis.