If the reason value carried in the SgNB_Add_Reject message is Transport resource not available, which of the following may be the cause of the problem?

If the reason value carried in the SgNB_Add_Reject message is Transport resource not available, which of the following may be the cause of the problem?
A . 5G side transmission failure leads to access rejection
B . Insufficient license for the number of users in the 5G community
C . Insufficient License
D . Insufficient PDSCH resources

Answer: A