In general, brittle deformation occurs at deformation

a. Higher temperatures

b. Higher pressures

c. Shallower depths of the Crust

d. Greater depths in the crust

Answer:

Shallow depth of crust 

Explanation:

Brittle deformation occur at Shallow depth of crust than ductile deformation. Shallow depth means low pressure low temperature. So when stress is applied on the material it get fracture. But in deeper level /high temperature pressure with the increasing stress strain the material become ductile/ plastic. In which fracture don't develp but deformation make the material to change its shape.(ductile deformation like fold).