Which of the following in text citations is/are correctly formatted according to the APA 7 guidelines?
a. Children show a weaker McGurk effect than adults (McGurk and MacDonald, 1976).
b. McGurk et al. (1976) examined the effect of visual information on speech perception in children and adults.
c. McGurk & MacDonald (1976) found a stronger McGurk effect in adults than children.
d. None of the other options are formatted correctly.