Decision Tree Image Classification

Hi All,

Currently, I am doing image classification using SVM and DT with the same training data and the same test image. The setting of SVM and DT used the default. There are four classes that I used (A, B, C, D). While in SVM training using Mdl = fitcecoc(trainset,class) it can classify all class, but in DT training using SVModelTree = fitctree(trainset,class) there are only three class A, C, D in the result and seems that the class B is classified as class C. Anycone can help me what causes of that? Thank you in advance.

Hend