Please answer the four questions

Which of the following learning problems is not a supervised learning problem? Select one: a. Clustering b. Regression c. Classification What datasets are used during neural network learning? Select one: a. training set and validation set b. learning set and testing set c. testing set d. validation set Which kind of the layer is not used in deep-learning ? Select one: a. Convolution layer b. Input layer c. Pool layer d. Reply layer e. RELU layer What sentence describes correctly the relationship between a person and a tattoo? Select one: a. A person may have only one tattoo and a tattoo must be tattooed on one person at least b. Each person must have at least one tattoo and a tattoo may be tattoed on one person c. A person may have more tattoos and a tattoo must be tattoed on more persons d. Each person may have more tattoos and a tatto must be tattooed on one person e. Each person must have one tattoo and a tattoo may be on one person