regarding dinner: I give 3 choices and then ask which one of them would be a good choice for dinner. I finally learned that my child is an over-thinker and overanalyzes everything and gets overwhelmed and responds with "I don't know" as a coping mechanism. Such kids find it easier when faced with a limited amount of choices.
As for what color she likes, when she says "I don't know", tell her that you have seen her wearing blue (or whatever other color she prefers) several times this month whereas you have not seen her wearing yellow at all and ask her if that is because she favors blue over yellow. Sometimes, it just helps a child reason well if we dropped clues for them. She is probably choosing colors by instinct and not noticing patterns in her action because she simply feels drawn towards some colors.
As for choosing classes for the upcoming grades, you are better off having conversations about this over a longer period of time. Discuss what each choice and path entails, bring up examples of college and career options available for each path, bring up your estimate of the workload that each option is associated with, bring up how other kids that you might know made choices and where they ended up now, bring up your own choices when you were a student and what motivated you at that time. I sometimes pull out a calendar app or even a sheet of paper and schedule in all the activities that my overachiever is raring to do and then show him how some things have to go to make room for something else.
For my child, we find that he can function well only if his main areas of interest were divided into 3 activities. He has other interests and hobbies which are not considered "main" activities. We usually divide a blank paper into 3 columns and write Academics, Extracurricular Sports, Extracurricular Fine Arts into the columns and allocate the productive hours of the week to those 3 slots. If my child wants to pick more fun Electives at school or a heavier Honors class load, I show him how the column for Academics grows very dense and the other two columns take a hit. It helps kids to make school choices when they can visualize how each choice impacts their free time and their whole school year.
As a funny aside: anyone in our household who answers questions like "How was your day?" etc using single-word answers have to come up with a 3-sentence answer before they are allowed to go on to do whatever they were trying to do. The parents are known to do this more often nowadays than the child.
