Final answer:
The Duodenal Switch is the bariatric surgery option that provides both restricted intake and significant malabsorption, leading to weight loss.
Step-by-step explanation:
The bariatric surgery that works by causing a restricted intake plus malabsorption of food is the Duodenal Switch (d). This surgery involves removing a large portion of the stomach and rerouting a lengthy segment of the small intestine, creating a shorter pathway for food to travel, which limits the absorption of nutrients and calories. In comparison, a Gastric Bypass (Roux-En-Y) surgery also restricts intake and causes some degree of malabsorption by creating a small pouch and rerouting the small intestine. However, the principal procedure known for its significant malabsorptive component combined with restricted intake is the Duodenal Switch.