Correct option is C. Both A and B
Testcross is a cross of any genotype showing dominant phenotype with a recessive homozygote to determine the genotype of a dominant parent if it is a heterozygous- or homozygous-dominant. Being a hybrid Tt shows dominant phenotype and tt is the recessive parent; it is a test cross. Option A is correct. Back cross is a cross between F$$_1$$ hybrid and any one of the parent (dominant or recessive) to deduce the genotype of both parents and the hybrid; here a hybrid “Tt” is crossed with recessive parents; it is a back cross. Option B is correct.