Step 1: Clarifying branched polymers.
Branched polymers consist of a primary linear chain with attached side branches. This branching impedes efficient packing, resulting in lower density compared to their linear counterparts.
Step 2: Evaluating the provided options.
- (A) HDPE: High Density Polyethylene is characterized as a linear polymer, lacking branching.
- (B) LDPE: Low Density Polyethylene is a branched polymer featuring side chains, thus fitting the description.
- (C) Nylon-66: This polymer is formed via condensation but does not exhibit branching.
- (D) PET: Polyethylene terephthalate is a linear polyester and is not branched.
Step 3: Final determination.
Option (B) LDPE is identified as the correct answer, being a representative example of a branched polymer.