I would really appreciate it if someone could give me a detailed answer about the stranded prepositions in the following sentences.
What makes a preposition strandable and what makes it unstrandable?

Which of the following are acceptable/correct and which aren’t and why?

a. Which grammar teacher did she forget the answer in front of?
b. Which vacation did John become ill during?
c. Who did you destroy a picture of?
d. I was astonished at the patience she spoke with.
e. What do you eat salad without?
f. What do you eat salad with?
g. The cheerfulness which she spoke with of the sad contrasts of her life.
h. The tone which she spoke with thrilled through me.
i. Which vacation did John go to Hawaii during?
j. Who did you destroy a picture of?
k. Which act did John leave the theater after?