Final answer:
Dinosaurs that weighed 10,000 kilograms or more were considered gigantotherms, as seen in some Cretaceous Period species like the Argentinosaurus. option d.
Step-by-step explanation:
Dinosaurs that weighed 10,000 kilograms or more were certainly gigantotherms. During the Cretaceous Period, dinosaurs like Tyrannosaurus rex, which weighed at least 7 tons (approximately 6,350 kilograms) achieved enormous sizes. Gigantothermy refers to the ability of large animals to maintain a stable internal body temperature due to their large volume-to-surface area ratio, which reduces heat loss. Some of the largest dinosaurs, such as Argentinosaurus, reached lengths of nearly 40 meters (130 feet) and weighed at least 80,000 kg (88 tons), dwarfing even the T. rex in size.