Step 1: Concept Explanation:
The question requires identifying the correct definition of a 'heroic couplet,' a key poetic form.
Step 2: Detailed Breakdown:
A 'heroic couplet' can be deconstructed as follows:
\[\begin{array}{rl} \bullet & \text{Couplet: Two successive lines of verse, typically rhyming and sharing the same meter.} \\ \bullet & \text{Heroic: In English verse, signifies iambic pentameter, the traditional meter for epic or 'heroic' poetry.} \\ \end{array}\]Therefore, a heroic couplet is defined as a rhyming pair of lines in iambic pentameter. This form gained prominence through Geoffrey Chaucer and was refined by poets like John Dryden and Alexander Pope during the 17th and 18th centuries.
Evaluating the other options:
\[\begin{array}{rl} \bullet & \text{(A) is incorrect as it relates to content, not the form itself. While found in heroic poems, the couplet is a structural element.} \\ \bullet & \text{(C) is incorrect. English tragedies (e.g., Shakespeare) primarily use blank verse (unrhymed iambic pentameter), not heroic couplets.} \\ \bullet & \text{(D) describes a quatrain, not a couplet.} \\ \end{array}\]
Step 3: Conclusion:
The correct answer is (B).