Which of the following is not a symptom of foot and mouth disease of cattle?

The answer to the question is option D, "blood-stained diarrhea". Foot and mouth disease is a highly contagious viral disease that affects cloven-hoofed animals such as cattle, pigs, sheep, and goats. The disease is characterized by the presence of sores on the feet, tongue, mouth, and occasionally on the udder. It also leads to excessive production of saliva and lameness, making it difficult for the animals to move. However, blood-stained diarrhea is not a symptom of foot and mouth disease. Instead, it may indicate the presence of other diseases such as bovine viral diarrhea or Johne's disease.