A group of 1000 5-week-old pigs has experienced a 2% death loss since weaning two weeks ago. most of the deaths were sudden; however, approximately 3% of the pigs showed clinical signs of lethargy, lameness, and labored breathing before dying. Postmortem examination of an affected pig shows severe fibrinous pleuritis, pericarditis, and peritonitis. Which of the following is the most likely causal organism?
a. Arcanobacterium suis
b. Escheria coli
c. Haemophilus parasuis
d. Salmonella cholerasuis
e. Streptococcus suis