Final answer:
The trust likely ran out of money since Shira graduated from college.
Step-by-step explanation:
A likely reason for the money stopping is option C, The trust ran out of money. Since Shira graduated from college, it's possible that the trust was specifically set up to provide financial support for her education. Once she completed her studies, the purpose of the trust may have been fulfilled, and there may no longer be funds available to continue making payments.