Final answer:
The guest with a birthday on February 5, 1999, turns 21 in the year 2020. Therefore, the correct answer is option B i.e. the year 2020
Step-by-step explanation:
To determine the year in which the guest turns 21, we will calculate the number of years from their birthday: February 5, 1999, to the year they reach the age of 21. Starting from the year 1999 and adding 21 years, we get 1999 + 21 = 2020. Hence, the guest turns 21 in the year 2020. To calculate a person's age take the difference between the current day and their birth day: days = current day - birth day . So we have to replace these differences in the following age formula: age = (years × 365) + (months × 31) + days .