The stress-strain curves are drawn for two different materials X and Y. It is observed that the ultimate strength point and the fracture point are close to each other for material X but are far apart for material Y. We can say that materials X and Y are likely to be (respectively),

CONCEPT:

• Brittle - A material is said to be brittle if subjected to stress onto the material and it fractures with little elastic deformation without significant plastic deformation.
• Plastic - Plastic deformation is defined as the permanent distortion which occurs when a material is subjected to compressive, bending, and tensile stresses which exceed its strength and causes the elongation, bend or twist.
• Ductile - Ductile is a defined property of the metal drawn into a thin wire called ductility and it is the property of metal associated with the ability to be hammered thin or stretched into wire without breaking.

CALCULATION:

When the stress-strain curves are drawn for two different materials X and Y. It is observed that the ultimate strength point and the fracture point are close to each other for material X but are far apart for material Y. 

Therefore, in ductile materials, we have fracture strength lower than the ultimate strength whereas, in brittle materials, the fracture strength is equivalent to the ultimate tensile strength.

Therefore, X is the brittle, and Y is the Ductile.

Hence, option 4) is the correct answer.