のどちらが

which of

→ の
phrase Rare #24,734
which of Used to ask which of two or more options is or does something. の links the options to どちら, meaning “which,” and が marks the choice being asked about.
JA: 電車とバスのどちらが早いですか。
EN: Which is faster, the train or the bus?

二つのうちのどちらが値段が高いんですか。

Which of the two is more expensive?

スケートとスキーのどちらがより好きですか。

Which do you like better, skating or skiing?

君達のどちらがいくのですか。

Which of you two is going?

「花子と太郎のどちらが若いですか」「太郎です」

“Who’s younger, Hanako or Taro?” “Taro is.”

ワシントンとニューヨークのどちらが、合衆国の首都ですか。

Which is the capital of the United States, Washington or New York?

ケンと太郎のどちらが背が高いですか。

Who is taller, Ken or Taro?