Here's a problem to solve: Ptolemy was an ancient astronomer who thought Earth was the center of the universe. When he made observations that were inconsistent with this, he proposed a phenomenon called "epicycles" to explain the observations. How was Ptolemy's process similar to the modern scientific process?

Among the 4 following options, which is the correct answer?

- A: Ptolemy based his model partly on a belief system.
 
- B: Observations inspired Ptolemy to modify his explanations.
 
- C: Ptolemy tried to describe the universe instead of explaining it.
 
- D: Experiments were the basis of Ptolemy's model of the universe.
 