What can be observed beneath a bright light on the passport card?

The correct answer is the RFID antenna because it is an integral part of the passport card’s design and functionality. When illuminated by a bright light, the RFID antenna can often be seen as part of the card's embedded technology. This antenna is responsible for transmitting data wirelessly to a reader, facilitating the secure and efficient processing of passport information.

While the other components mentioned, like the microchip and hologram, may have distinct appearances under certain conditions, they do not typically become apparent simply by shining a bright light. The holder's picture is printed on the card but is not designed to be prominently highlighted in this way. Therefore, identifying the RFID antenna beneath a bright light highlights understanding of the technology embedded in modern passport cards.