The correct answer is B. It is the only one that should be written with periods - a.m., meaning - ante meridiem, or 'before noon'. The other examples are written without a period.
Answer:
Which of the following abbreviations requires the use of a period or periods?
B. PA (the abbreviation for Pennsylvania)
C. Fe (the chemical symbol for iron)
D. YWCA (an organization for young women
Explanation:
Penn Foster