Question

which fat is solid at room temperature

Explanation:

Saturated fats (like butter, lard) have a straight molecular structure, allowing them to pack closely, so they're solid at room temperature. Unsaturated fats (like oils) have kinks from double bonds, preventing close packing, so they're liquid.

Answer:

The fat that is solid at room temperature is saturated fat (the option with the butter - like image labeled "saturated fat").