Final answer:
The sentence 'He sat under the boughs of a spreading tamarind tree, which flanked a path.' is correctly rewritten as 'Sitting under the boughs of a spreading tamarind tree, which flanked a path.', so the answer is c) Sitting.
Step-by-step explanation:
The question asks to rewrite the sentence using the 'ing' form of the underlined word. The sentence provided is: 'He sat under the boughs of a spreading tamarind tree, which flanked a path.'
The correct rewriting of the sentence with the 'ing' form of the underlined word (sat) is: 'Sitting under the boughs of a spreading tamarind tree, which flanked a path.' Therefore, the correct answer is c) Sitting.