question_answer

Fruit shape in shephered's purse (Capsella bursa) is of two types-triangular and top-shaped. Triangular fruit shape (T) is dominant over top-shape (t). Following table summarises the results of several crosses:

Cross	Result
Strain 1 \[\times \] tt	All triangular
Strain 2 \[\times \] tt	1 triangular: 1 top-shaped
Strain 3 \[\times \] tt	All top-shaped
Strain 4 \[\times \] Tt	3 triangular : 1 top-shaped

Which pair of strains possesses the genotype Tt?

A)  Strains 2 and 3

B)         Strains 2 and 4

C)  Strains 1 and 3

D)  Strains 1 and 4