What is the difference between 'talk' and 'talk to'?

Test No. [color=blue]incompl/elem-18 “Making an Appointment”, question 6

You arrange an appointment with another person because you want to or see them.

(a) encounter
(b) greet
© meet
(d) talk

Test No. [color=blue]incompl/elem-18 “Making an Appointment”, answer 6

You arrange an appointment with another person because you want to meet or see them.

Correct answer: © meet
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what is wrong when you use ‘talk’ in this sentence?

Talk requires a preposition: You can talk [color=blue]to or [color=blue]with a person.[YSaerTTEW443543]

TOEIC listening, photographs: The warehouse[YSaerTTEW443543]