Answer:
Answer C, register for the PSAT
Explanation:
While the PSAT can also be taken in sophomore year, every other choice in the list is something that needs to be done senior year, I'll go down the list.
The essay you write for a college usually is part of the application process, which you almost certainly will be doing senior year.
Letters of recommendation that are a year old look much less convincing than letters dated around the time of your application.
Your final transcripts aren't even available until your senior year because your senior year grades need to go on it.
