Answer:
b. inside stars and supernovae
Step-by-step explanation:
The most massive elements, including those found in rocky planets like Earth, were formed through the process of nucleosynthesis inside stars and during supernovae events. Stars are massive furnaces that fuse lighter elements, such as hydrogen and helium, into heavier elements through nuclear reactions. This process, known as stellar nucleosynthesis, produces elements up to iron in the periodic table.
However, elements heavier than iron, such as gold, uranium, and lead, are predominantly formed during supernovae explosions. When a massive star reaches the end of its life, it undergoes a catastrophic explosion known as a supernova. The immense heat and pressure generated during a supernova create the conditions necessary for the synthesis of these heavy elements through rapid neutron capture, also called the r-process.
After these elements are formed, they are dispersed into space, eventually accumulating in molecular clouds and planetary systems, including rocky planets like Earth. Therefore, the most massive elements found on Earth and other rocky planets were primarily formed through the processes occurring inside stars and during supernovae.
hope this helps!