Answer: d. apology
Explanation: Apology means to express one's regret, to feel sorry,
E.g. She accepted your apology.
Answer: c. beneficial
Explanation: Beneficial means advantageous, favourable, profitable, etc.
E.g. Good sleep is beneficial to health.
Answer: a. Completeness
Explanation:E.g. We had a sense of satisfaction and completeness.
Answer: b. delivery
Explanation: E.g. The delivery charges will be charged for orders below Rs. 999.
Answer: c. existence
Explanation: E.g. The existence of aliens is suspicious.
Answer: d. furniture
Explanation: Furniture - chairs, tables, etc. required for use or as an ornament.
E.g. She replaced her old furniture.