Question: What is the minimum channel spacing for intra-band contiguous carrier aggregation with two or more component carriers, unless stated otherwise?
Option 1: Any multiple of 300 kHz
Option 2: The difference between the channel bandwidths of the two respective E-UTRA component carriers
Option 3: A fixed value of 15 MHz
Option 4: The sum of the channel bandwidths of the two respective E-UTRA component carriers
Explanation: According to the 3GPP specification, for intra-band contiguous carrier aggregation with two or more component carriers, the nominal channel spacing between two adjacent E-UTRA component carriers can be adjusted to any multiple of 300 kHz less than the nominal channel spacing. This allows for optimization of performance in a particular deployment scenario.