Final answer:
Mitochondrial DNA supports the endosymbiotic theory, indicating that mitochondria originated from prokaryotic cells, confirmed by similarities between mtDNA and bacterial DNA. The correct option is a.
Step-by-step explanation:
The presence of mitochondrial DNA (mtDNA) in eukaryotic cells supports the traditional view of the origin of mitochondria and is in line with the endosymbiotic theory. This theory posits that mitochondria originated when a eukaryotic cell engulfed a prokaryotic cell, which then developed into a symbiotic relationship. The endosymbiotic theory is reinforced by the fact that mitochondrial DNA resembles the DNA found in bacteria and has several homologous features such as circular structure, similar genes, and a prokaryote-like method of replication through binary fission. Therefore, the correct answer is: A. Supports; because mtDNA is similar to bacterial DNA.