Good quiz idea but needs a lot of work! "Es" means just "it", which explains why so few have it right. "It is" would be "es ist". Bitte can also mean "you are welcome" and since you have this word following danke, that's an obvious translation. "Sie" can also be translated as "they" or "you".
"Ein" is an indefinite article, neuter or masculine singular. "Der", "die", "das" are definite articles in the singular. "Ein" means "one" or "a/an" in English.
How can you be "pretty sure" of something entirely incorrect?