Appropriate question word to use

[Jaffa]

Hello,

I am having trouble determining which question word should go in the brackets in the following:

Person 1:（？？）ケーキを かいましょうか。
Person 2: それが いいです。

I think it could be どんな but I don't understand what Person 2 is saying (in particular それが) and it's making me confused. I think it might saying "that's good"...

Thank you for the help.

 

[Toritoribe]

"I prefer that one" makes sense?

いい

［７］【好む】like;（より好む）prefer (-rr-).

彼女のどこがいいんだ
What do you like about her?

彼のいいように（＝好きなように）させておけ
Let him do as he likes [pleases, 書 wishes]./Let him have his own way.

会話

「ステーキはどんな焼き具合のがいいですか」 「ミディアムがいいです」 "How would you like your steak?""I'd like it [mine] medium."（※単にMedium, please.（ミディアムにしてください）と答えてもよい）

車で行くより歩いて行く方がいい
I like walking better [more] than riding.（※betterが普通.→好き1）/I prefer walking to [☓ more than] riding./I prefer to walk rather than (to) ride [☓ than riding]./I would [I'd] rather walk than drive [☓ walking than driving].（※I'd ratherはくだけた言い方ではしばしばI rather...となる）

会話

「てんぷらがいいですか,刺身がいいですか」 「てんぷらの方がいいです」 "Would you liketempura orsashimi?""I'd prefer tempura, please."（※would like [prefer]は「好き嫌い」ではなく,特定場面での穏やかな「希望」を表わす.また後に不定詞は続くが,動名詞は不可: I'd like [prefer] to eat [☓ eating] later.）

「いい」の検索結果 - Yahoo!辞書

 

[Jaffa]

Oh. I didn't know いい can also mean prefer. So I guess the question word どの and not どんな should be used. Makes more sense that way. Thank you very much.