Right option is (a) 1 mV
Easiest explanation: Foetal electrocardiogram is recorded by suitably placing the electrodes on the mother’s abdomen and recording the combined maternal and foetal ECG. The maximum amplitude of FECG (R wave) recorded during pregnancy is about 100 to 300 mV. This magnitude is much smaller than in the typical adult ECG which is about 1 mV in the standard lead connection.