Step 1: Concept Identification: The query concerns the thematic elements within the Gandatindu Jataka. Jataka tales are Buddhist narratives detailing the Buddha's past lives, primarily serving as moral instruction and occasionally reflecting contemporary socio-political contexts.
Step 2: Detailed Exposition: The Gandatindu Jataka recounts the narrative of King Panchala. The story illustrates how the king, by adopting the guise of a commoner, gains knowledge of his subjects' distress.
(A) Cordial relationship...: This assertion is erroneous. The narrative's core premise is the absence of a cordial relationship and the king's lack of awareness regarding his subjects' suffering.
(B) The plight of the subjects of a wicked king: This represents a principal theme. The populace is portrayed as enduring hardship under the king's governance.
(C) The strained relationship, especially with the rural population: The narrative emphasizes the particular oppression and fear experienced by the rural populace concerning the king's officials.
(D) ...demanding high and oppressive taxes: This constitutes the primary catalyst for the subjects' plight described in the story. The king's tax collectors exhibited extreme ruthlessness, prompting inhabitants to abandon their villages.
Step 3: Conclusive Determination: Statements (B), (C), and (D) accurately delineate the content of the Gandatindu Jataka. Statement (A) presents a contrary depiction. Consequently, the correct selection comprises only (B), (C), and (D).