The verb, ser, is in the singular el/ella/usted tense, meaning that the subject is only one person or thing. This eliminates the two middle choices, as they are multiple people.
Next, the adjective. Alto is in the masculine form, so Maria, as it is a girl name, is also able to be eliminated.
The correct answer would be Tomas.
I can help
what spanish are you in?
Is there a story of Juan and Pedro to read before answering this because i havent red about them.