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Let's go through the answers together.
Perhaps the easiest to look at is good old Ralph Waldo Emerson.
Ralph is one identifier.
Emerson is one identifier. 1803 is a number.
It's transcendental-tastic.
This totally matches the pattern we're looking for.
By contrast, Henry is an identifier.
Thoreau is an identifier, but these 2 slashes begin an end of line comment,
so we'll never see the 1817, so this one does not match.
Down here, Marie Curie 1867, this would be identifier, identifier, number,
except that the whole thing is canceled out by this end of line comment
that starts over here.
Then up here, her daughter, Irene, this is one identifier.
This connected by an underscore is just one more identifier.
Here's a number.
We match perfectly so far.
It looks like we'd stop matching because of this fourth number,
but since it's in a comment, we ignore it, so both of these work.
And Marie Curie is relatively well known as a Polish physicist and chemist.
She was the first person to hold Nobel prizes,
quite a feat, one in physics and one in chemistry,
and in fact, she named the element polonium after her home country.
Thoreau wrote "Walden," which is relatively well known,
a book about being self-reliant and dependable
in which he starts on the first page by borrowing an ax from his neighbor.
Marie Curie's daughter, Irene, also went on to win a Nobel prize
for the discovery of artificial radioactivity.