In this question, we are given a list of discoveries and a list of scientists. We need to match each discovery with the correct scientist.

List I:

A. Circulation of blood - William Harvey

B. Stethoscope - Rene Laennec

C. X-ray - Wilhelm C. Roentgen

D. Electro-cardiogram (ECG) - Willem Einthoven

List II:

1. William Harvey

2. Wilhelm C. Roentgen

3. Willem Einthoven

4. Rene Laennec

We can see that the correct matches are:

A. Circulation of blood - William Harvey

B. Stethoscope - Rene Laennec

C. X-ray - Wilhelm C. Roentgen

D. Electro-cardiogram (ECG) - Willem Einthoven

Therefore, the correct answer is option 1: A - 1, B - 4, C - 2, D - 3.

Each option has a different combination of scientist and discovery. Option 2 does not have the correct match for the circulation of blood, which is William Harvey. Option 3 does not have the correct match for the stethoscope, which is Rene Laennec. Option