阅读下列短文,从每题所给的A、B、C和D四个选项中,选出最佳选项。
A
San Francisco better local garden
The San Francisco Botanical Garden is one of the most diverse gardens in the world. The garden is a living museum within Golden Gate Park, offering 55 acres(英亩)of both beautiful gardens and open spaces. 
The garden is open during COVID-19. It is free to all San Francisco residents and garden members. We are also continuing to offer free admission every morning to everyone from 7:30 am to 9 am—a fantastic time for bird-watching. The second Tuesday of the month is also free to everyone. 
Free Day:
Second Tuesday of every month;Free daily from 7:30 am to 9 am;Always free for San Francisco city and county residents;Always free for garden members and school groups. 
Regular Cost:
Adults $9;Foreign adults $12;Youth and seniors $7;Children $3;Children 4 years old and younger free. 
Last Entry:
Fall and winter:October through early November(Last entry at 5 pm);First Sunday in November through January(Last entry at 4pm);February through second Saturday in March(Last entry at 5 pm). 
Spring and summer:Second Sunday in March through September(Last entry at 6 pm). 
(The garden closes one hour after last entry. )
21. What do we know about the San Francisco Botanical Garden? 
A. It is closed during COVID-19.          B. It is free for local people. 
C. It is free for everyone on Tuesday.       D. It is located near Golden Gate Park. 
22. How much does it cost a foreign adult to visit the garden on weekdays? 
A. $3.       B. $7.       C. $9.       D. $12. 
23. At which of the following time can visitors enter the garden? 
A. At 4pm in June.        B. At 5 pm in December. 
C. At 7pm in March.       D. At 6 pm in February.