Basic shapes: Discussing the shape of elements in a chart

💬 [この] must come right before a noun: [このグラフ], [この形]. If you want to say "this one" by itself, use [これ] instead.

💬 [この] has to be followed by a noun, so [このグラフ] is natural but [この] alone is not. For "this" on its own, use [これ].

💬 [どれ] means "which one" when the thing is not named right after it. If you do name it, use [どの] + noun, like [どの形]?

💬 [がいい] is a very common way to ask or say what is preferable: [どれがいい？] "Which is better?" or [これがいい] "This one is good / I prefer this one."

💬 [どれ] means "which one," so use it when you are choosing among things without naming the category. If you do name the category, switch to [どの] + noun, like [どの形がいい？].

💬 [どの] has to come before a noun: [どの形], [どのグラフ]. If you want "which one?" by itself, use [どれ].

💬 [どの] must be followed by a noun, while [どれ] stands alone. So [どの形がいい？] names the type of thing, but [どれがいい？] leaves it unstated.