An engineer is configuring Cisco IOS-based MTP for video call. Which requirement must be met?

There is no requirement to set minimum sessions to 4 for video support on an IOS-based MTP; session count parameters are independent of video capability.

Setting maximum sessions to 100 is a capacity configuration parameter and has no bearing on whether video calls are supported.

IOS-based MTPs do not support video transcoding, so passthrough mode must be enabled to allow video media streams to pass through without modification. Without passthrough enabled, the MTP would attempt to process the video stream in a way it cannot support, causing the video call to fail. Passthrough mode instructs the MTP to relay the media stream unchanged between endpoints.

Disabling passthrough would prevent the IOS-based MTP from handling video calls, since IOS MTPs cannot transcode video codecs and require passthrough to relay video media.