To solve this problem, we need to analyze each statement about basophils:$\newline \bullet$A. Basophils are the most abundant cells of the total WBCs.$\newline$ - This statement is incorrect. Neutrophils are the most abundant white blood cells, not basophils. Basophils are the least abundant.$\newline \bullet$B. Basophils secrete histamine, serotonin, and heparin.$\newline$ - This statement is correct. Basophils release histamine, serotonin, and heparin, which are involved in inflammatory responses.$\newline \bullet$C. Basophils are involved in inflammatory response.$\newline$ - This statement is correct. Basophils play a role in the inflammatory response by releasing histamine and other mediators.$\newline \bullet$D. Basophils have a kidney-shaped nucleus.$\newline$ - This statement is incorrect. Basophils have a lobed nucleus, not a kidney-shaped one. Monocytes have a kidney-shaped nucleus.$\newline \bullet$E. Basophils are agranulocytes.$\newline$ - This statement is incorrect. Basophils are granulocytes, as they contain granules in their cytoplasm.$\newline$Based on the analysis, the correct statements are:$\newline$B and C only.$\newline$Therefore, the correct option is Option 3: B and C only.