Which additional instrument experience is required to meet the recent flight experience requirements to act as pilot in command of an airplane under IFR?

The correct answer reflects the current regulations governing the recent flight experience requirements for acting as pilot in command under Instrument Flight Rules (IFR). Specifically, the requirements stipulate that a pilot must complete four instrument approaches – which can be performed in an airplane, an approved flight simulator, or a training device. This provision is essential as it ensures that pilots are proficient and adequately prepared to operate safely in IFR conditions, where navigation relies heavily on instruments.

Completing four instrument approaches not only validates a pilot's ability to conduct landing procedures in poor visibility but also ensures familiarity with the aircraft's instruments and navigation systems. The option including the allowance for a flight simulator or training device further enhances training flexibility, enabling pilots to maintain proficiency even when actual flight time may be limited.

In contrast, the other choices do not align with the specific requirements established by the regulations. For instance, requirements for fewer approaches or different types of aircraft do not meet the standard, thus highlighting the importance of adhering strictly to the four-instrument-approach guideline to ensure operational safety and compliance with regulatory standards.