Concept:
The Renaissance was a period of cultural rebirth in Europe.
It produced outstanding developments in painting, sculpture, architecture, literature, science, and humanistic thought.
Step 1: Check Assertion (A).
The assertion says that some of the greatest achievements of the Renaissance were made in painting, sculpture, and architecture.
This is correct.
Artists such as Leonardo da Vinci, Michelangelo, Raphael, and Brunelleschi made major contributions to Renaissance art and architecture.
Step 2: Check Reason (R).
The reason says that the Renaissance was marked by the rise of great artists with individuality and prestige.
This is also correct.
Renaissance artists were not merely craftsmen; they were respected as creative individuals.
Step 3: Check explanation.
The rise of talented artists with individual style explains why the Renaissance produced great achievements in art and architecture.
Thus, Reason correctly explains Assertion.
Step 4: Final conclusion.
Both statements are correct and Reason is the correct explanation of Assertion.
Hence:
\[
\boxed{\text{(A)}}
\]