Could you tell me why do I need to add article 'the' in this sentence?
The last eruption of the Kilimanjaro volcano happened about 200 years ago.
It's taken from an English app. The word in bold is the answer suggested by the app. The original options are (an/the/-/a). I chose (-) (no additional article), but my answer was marked wrong. There's also the lesson section to review some topic related to the test given. It says:
Names of countries in the singular, summits of mountains, continents, towns don't use the definite article:
Names of countries in the plural, mountain ranges, regions use the definite article:
the Rocky Mountains
Do we need it because THE before a noun is required when the other person knows which thing we are referring to? OALD defines a volcano as a mountain with a large opening at the top through which gases and lava (= hot liquid rock) are forced out into the air, or have been in the past. If that the case, shouldn't the answer be (-)?