Final answer:
The correct answer to the question about a big spotted cat's ballet suit is 'tutu', which is the term for a type of costume worn by ballet dancers. The question is a playful reference to the visual similarity between the spots of a leopard and the design of a ballet tutu.
Step-by-step explanation:
The question requires identifying the correct word related to a big spotted cat's ballet suit. The correct answer is (a) Tutu. A tutu is a type of costume worn by ballet dancers, typically characterized by a skirt made of tulle or a similar fabric, designed to stand out from the dancer's body. Although the question is phrased in a playful manner relating a 'big spotted cat' to a ballet suit, suggesting a visual similarity between the spots of a leopard or similar large cat and the look of a tutu, the focus here is on identifying that the ballet suit being referred to is a tutu.
The other options provided are not related to ballet attire: (b) Tuba is a musical instrument, (c) Tuna is a type of fish, and (d) Tufa is a variety of limestone. None of these relate to a ballet suit or the theme of the question, leaving tutu as the only logical answer.