What is the maximum number of equal-cost paths that EIGRP can load balance across by default?

Correct answer: 4 paths

Option D is correct because EIGRP defaults to a maximum of 4 equal-cost paths for load balancing, controlled by the 'maximum-paths' command, which can be raised to a maximum of 32 on modern IOS versions, but the out-of-the-box default is 4. Option A is wrong because EIGRP does not support unlimited paths; it has a configurable maximum with a defined default, and leaving load balancing unbounded would create unpredictable traffic distribution. Option B is wrong because 6 paths is not the EIGRP default; while some routing protocols or configurations support 6 paths, EIGRP's default maximum-paths value is 4. Option C is wrong because 2 paths is not the EIGRP default; that value is associated with some other protocols or manually constrained configurations, not with EIGRP's out-of-the-box behavior.