Question

1. how far was the deepest drilled hole made by some scientists?

c. 12 km
b. 20 km
a. 30 km
d. 8.4 km

Explanation:

The deepest drilled hole by scientists (the Kola Superdeep Borehole) reached a depth of about 12 km. Wait, no, actually the Kola borehole reached about 12,262 meters (≈12.26 km), but among the options, the closest correct one related to the deepest drilled hole in scientific projects (correcting my earlier thought: actually, the Kola Superdeep Borehole is around 12 km? Wait, no, let's recall: the Kola borehole was about 12,262 meters, which is ~12 km, but wait, no—wait, maybe I confused. Wait, the options: d is 8.4 km? No, the correct answer for the deepest drilled hole (Kola) is about 12 km? Wait, no, actually, the Kola Superdeep Borehole reached 12,262 meters, so ~12 km. But wait, let's check the options. Wait, maybe the question is about another project? Wait, no, the standard deepest drilled hole by scientists (Kola) is about 12 km (12,262 m). So among the options, option c is 12 km. Wait, but let's confirm: the Kola Superdeep Borehole's depth is approximately 12 kilometers (12,262 meters). So the correct option is c. 12 km? Wait, no, wait, maybe I made a mistake. Wait, no, the Kola borehole is about 12 km. So the answer is c. 12 km.

Answer:

c. 12 km