Gap-fill exercise

Below is a short conversation between two people as they talk on their mobile phones. Complete the conversation with the missing location prepositions.Use the "Hint" button to get a free letter if an answer is giving you trouble. Note that you will lose points if you ask for hints!
A. Where are you?
B. I am [at, to, in, on] the corner waiting for you. Where are you?
A. I am standing [at, to, in, on] the footpath waiting for you.
B. Can’t you see me? I am [at, to, in, on] the corner!
A. Oh, there you are.
B. I was standing [at, to, in, on] the shop entrance, but you couldn’t see me, so I moved [at, to, in, on] the corner.