Is there any method of measuring impedance at low frequencies below 100 kHz with the 4395A-010?

The option 4395A-010 is designed to measure impedance at frequencies above 100 kHz and, thus it is specified for the range above 100 kHz. As a matter of fact, the option 4395A-010 can measure and display impedance at frequencies below 100 kHz though accuracy is not specified for the low frequency range. If you want to acquire somehow impedance values (regardless of the specifications) at frequencies below 100 kHz, the IFBW should be set as narrow as possible and the source power should be set as large as possible.