Which of the Following Describes the Typical Characteristics of What

Which of the following describes the typical characteristics of what is commonly known as "Russian current"?

A) Direct current interrupted every 5 seconds for 10 second intervals
B) Biphasic pulsed current, frequency greater than 100 pulses per second with 10 second interpulse intervals
C) Monophasic pulsed current, 100 μsec twin-peaked pulses and 9,900 μsec interpulse intervals
D) 2,500 Hz alternating current, burst modulated at 50 bursts per second using 10-msec bursts