Answer
J430
Case 1 Yes
Case 2 Your in G?
Case 3 No don't fly on you will be in D
The answer is C over D clearance from tower
E over D clearance not required
There is no gap in the middle
The confusion could be in the phraseology used in your example that the tower had no requirement for you on frequency as opposed to you not requiring a clearance.
Excerpts relevant
Class - C
Type of flight - VFR
Separation provided - VFR from IFR
Service provided - 1. Air traffic control service for separation from IFR 2. VFR / VFR traffic information (and traffic avoidance advice on request).
Speed limitation - 250 KT IAS below 10,000 FT AMSL *
Radio communication requirements - Continuous two-way
Subject to an ATC clearance - Yes
Class - D
Type of flight - VFR
Separation provided - NIL (meaning segregated from IFR)
Service provided - Air traffic control service, traffic information on all other flights.
Speed limitation - 250 KT IAS below 10,000 FT AMSL *
Radio communication requirements - Continuous two-way
Subject to an ATC clearance - Yes
Class - E
Type of flight - VFR
Separation provided - NIL (meaning nothing)
Service provided - Flight Information Service
Speed limitation - 250 KT IAS below 10,000 FT AMSL *
Radio communication requirements - Continuous two-way
Subject to an ATC clearance - NO