Concept:
In English grammar, the correct past participle of the verb “bear” in the sense of birth is “born,” not “borne.”
Step 1: Identify the incorrect word in the sentence.
The sentence begins with:
\[
\text{He was borne of poor parents}
\]
Here, the word:
\[
\text{borne}
\]
has been incorrectly used.
Step 2: Understand the difference between “born” and “borne”.
• Born → used in the context of birth
• Borne → means carried or tolerated
Step 3: Write the correct expression.
The correct sentence should be:
\[
\text{He was born of poor parents.}
\]
Step 4: Check the remaining parts.
• but brought up → correct
• in an affluent family → correct
Step 5: Conclusion.
Thus, the error lies in part:
\[
\boxed{\text{(A) He was borne of poor parents}}
\]