I have a question about grammar and usage. Please help.
たち食いそば屋は、座らないで「?」そばを食べる店です。
The question is what grammar form should be inserted there. My book answer is 立って not 立ちながら.
But what is wrong with the latter?
P.S.
I'm not sure whether this is a relevant info but the question is from an N1 Jlpt test. Does that mean that ながら, which is enlisted in N5 level, is not the appropriate answer?