The correct options are
A They represent data through pictures.
C They look attractive and attract readers attention.
D They help us to answer the question on the data easily.
A pictograph represents data through pictures of objects. It helps answer the questions on the data at a glance. So it look attractive and attract reader's attention.
They can be applied to any data set but it can be so difficult.
Suppose if you have to represent sales of cars for a company in a year, it will be so difficult to represent data like 39837 or 30001, using pictures, in which cases, scaling can be used.