Did the original Greek scriptures use upper and lower case letters, in particular for "Holy Ghost"? Most English translations captialize "Holy Ghost".

Which is true:


The original Greek capitalized it too.
The original Greek capitalized proper nouns, but not these.
The original Greek didn't capitalize proper nouns.


The last two would imply that the English capitalization is due to the Trinitarian beliefs of the translators.

Added clarification: By "capitalization" I don't necessarily mean literal capital letters, but any equivalent textual convention that identifies proper nouns (e.g. "John Baker's father was a baker." would be ambiguous without the B/b distinction).
Actually none of the above. The original Greek manuscripts were written in all capital letters. The minuscule script (which evolved into the Greek lowercase) was developed only during the 9th-10th centuries.

Capitalising "Holy Ghost" does not imply Trinitarian theology, all it says is that the translators think it is a proper noun. There are many theological positions which would identify "Holy Ghost/Spirit" as a proper noun without accepting Nicene or Chalcedonian Trinitarian theology, such as gnosticism, modalism, Arianism, Mormonism, and many more.