The cat/The kitten or the kitten?

[Sped Tiger]

Could you tell me, please, whether the first word of the second option separated from the first option by a slash should also be capitalized if it begins a sentence? I believe that it should be, since it's illogical to only capitalize the first option, as, if you choose the second one, the first word is to be capitalized anyway.
So, which is correct? (I personally speculate the first is correct.)
1. The cat/The kitten has fled.
2. The cat/the kitten has fled.

 

[5jj]

Try: The cat/kitten has fled.

 

[emsr2d2]

As 5jj has indicated, there's no need to repeat the article provided the article is the correct one for both options. It would be different with the indefinite article depending on the noun used:

A cat/kitten is sitting outside my window. (Both nouns take "a".)
An elephant/iguana is eating a banana. (Both nouns take "an".)
A dog/An ocelot has fallen down a hole. (The two nouns take different articles so you'd have to use both and capitalise them both.)