Question: What is the purpose of using Cause No. 47 "resource unavailable, unspecified" in mobile radio interface Layer 3 specification?
Option 1: To report a resource unavailable event when no other specific cause applies.
Option 2: To indicate that a resource is available but not allocated.
Option 3: To signal that a resource is being released due to inactivity.
Option 4: To notify that a resource is being reallocated to another user.
Explanation: Cause No. 47 "resource unavailable, unspecified" is used as a catch-all cause when no other specific resource unavailable cause applies, allowing the network to report an unspecified resource issue without providing further details.