Final answer:
In APA citation style, the blank should be filled with the author's name, 'a. Barron, J.', following the standard format for a newspaper article citation.
Step-by-step explanation:
According to APA citation style, the blank in the citation "(April 2010). 'News business lags at high schools, too.' The New York Times, 12." should be filled with the name of the author or group author if it's known. Since the provided options include author names and publishers, the correct citation element to fill in the blank is option a. Barron, J. This fits the APA format for a newspaper article, which typically includes the author's last name and first initial.
The citation would look as follows:
Barron, J. (April 2010). 'News business lags at high schools, too.' The New York Times, 12.