cannot be answered.
If we assume that the closing prices have a normal distribution then we
would be looking at the t table with 35 degrees of freedom (as 35 is a small
sample for these purposes). But without this assumption all we can say
Now it might be that you are expected to make some assumtion but without
seeing your notes we don't know if you are supposed to treat 36 as a large
number and so use the z table, or assume the closing prices are normal, but
36 is small and so use the t table.