You work as a machine learning specialist for a robotics manufacturer where you are attempting to use unsupervised learning to train your robots to perform their prescribed tasks. You have engineered your data and produced a CSV file and placed it on S3.
Which of the following input data channel specifications are correct for your data?

Answer options:

A.Metadata Content-Type is identified as text/csv
B.Metadata Content-Type is identified as application/x-recordio-protobuf;boundary=1
C.Metadata Content-Type is identified as application/x-recordio-protobuf;label_size=1
D.Metadata Content-Type is identified as text/csv;label_size=0

Answer: D
Option A is incorrect. The Content-Type of text/csv without specifying a label_size is used when you have target data, usually in column one, since the default value for label_size is 1, meaning you have one target column. (See the Amazon SageMaker developer guide titled Common Data Formats for Training)
Option B is incorrect. The boundary content type is not relevant to CSV files. It is used for multipart form data.
Option C is incorrect. For unsupervised learning, the label_size should equal 0, indicating the absence of a target. (See the Amazon SageMaker developer guide titled Common Data Formats for Training)
Option D is correct. For unsupervised learning, the label_size equals 0, indicating the absence of a target. (See the Amazon SageMaker developer guide titled Common Data Formats for Training)
Reference:
Please see the Amazon SageMaker developer guide, specifically Common Data Formats for Built-in Algorithms and Common Data Formats for Training.