One way to ask someone what they want is to ask their preference. They will tell you that they either want udon noodles or soba noodles. This is a formal way to ask.
I hope that this helps :)
Which would you like: udon noodles or soba noodles?
When you want to ask your customer which of the two available options they prefer, then you can ask in the following ways:
-Would you like udon noodles or soba noodles?
-Would you prefer udon noodles or soba noodles?
-Which would you like: udon noodles or soba noodles?
お客さんに二つの選択股からどちらがいいか尋ねたい時は、次のように聞くことが出来ます。
【例文】
-Would you like udon noodles or soba noodles?
（うどんがいいですか、それともそばがいいですか？）
-Would you prefer udon noodles or soba noodles?
（うどんの方がいいですか、それともそばがいいですか？）
-Which would you like: udon noodles or soba noodles?
（うどんかそば、どちらがいいですか？）
You can simply say, "Would you like udon or soba noodles?" It is direct and to the point. You need something simple and to the point, while working in a restaurant.
シンプルに：
"Would you like udon or soba noodles?"
「うどんかそば、どちらがいいですか」
と言えます。ストレートな言い方で、的を射ています。
レストランで働く場合、シンプルでストレートな言い方がいいです。
Your options are: Udon or Soba noodles. Which would you prefer?
When giving someone an 'option', you are giving them a choice to choose from two or more options. In this case, it is two options of noodles. Their selection all depends on their preference as to taste in food, portion size or price, etc.
People usually like having options when it comes to food. It makes them feel more in control of what they'd like to eat and this will determine how much they enjoy the food.
In the UK people do not have a clue what udon or soba is. If you wish to keep the conversation on track and short you may just refer to flour or buckwheat, both of which are more familiar terms.
Which would you like, soba noodles, or udon noodles? Soba is the grey noodles made of buckwheat. Udon is the white noodles made of flour and they are thicker.
Would you like soba noodles or udon?
Which would you like to put in your okonomiyaki, soba noodles or udon?
蕎麦のことはsoba noodlesと言います。蕎麦はbuckwheat（そば粉）で出来ている、と言ってあげるとヘルシー通には喜ばれると思います。うどんはudon noodlesです。Flour（小麦粉）で出来ています。
Soba is the grey noodles made of buckwheat. は、蕎麦はそば粉で出来た灰色の麵です、という意味です。grey（灰色）は言わなくて良いかもしれませんが。
どちらが良いですか？というのは、紅茶かコーヒー、チキンかビーフ、などでも同じです。
Which would you like, 〜 or ー？ 「〜かー、どちらが宜しいでしょうか。」
Would you like 〜 in your okonomiyaku, or ー？「お客様のお好み焼きには〜が宜しいですか、それともーですか？」
Would you like 〜 or ー？ 「〜 か ー、どちらが宜しいでしょうか？」
We have two kinds of noodles, 〜 and ー. Which would you like in your okonomiyaki? 「私たちは、〜 と ー、２種類の麵を扱っています。お客様のお好み焼きにどちらが宜しいでしょうか？」
Which would you like in your okonomiyaki, 〜 or ー 「お客様のお好み焼きには、〜 か ー、どちらが宜しいでしょうか。」
If you are asking something what they want then you would ask 'would you like?' if you are asking which one they would like more then you would say 'would you prefer?'
'udon or soba noodles describes what they are choosing from
相手の好みを聞くときは、'would you like?' と言えます。
二つのうちどちらがいいか尋ねるなら、'would you prefer?' と言えます。
'udon or soba noodles'（うどんかそばか）はその選択肢です。
アメリカ合衆国 
南アフリカ 
カナダ 
イギリス 
日本 
