Question: What is the condition for a PDCCH consisting of consecutive CCEs to start on a specific CCE?
Option 1: The CCE number must be even.
Option 2: The CCE number (n) must fulfill n mod 4 = 0, where n is the CCE number.
Option 3: The CCE number must be odd.
Option 4: The CCE number must be a multiple of 9.
Explanation: According to the text, a PDCCH consisting of consecutive CCEs may only start on a CCE fulfilling n mod 4 = 0, where n is the CCE number. This ensures that the PDCCH starts at a specific alignment within the control channel elements.