A CustomerOrders DynamoDB table has following items.
CustomerName (PK)
Order Item
Cost
Albert Einstein
Candle
15
Albert Einstein
Spaceship Toy
50
Albert Einstein
Hair Comb
5
Isaac Newton
Bag of Apples
25
Following operation is executed:
aws dynamodb query \
 --table-name CustomerOrders \
 --key-condition-expression " CustomerName = :name " \
 --filter-expression "Cost > :amount" \
 --expression-attribute-values `{
 ":name": { "S": "Albert Einstein" },
 ":amount": { "N": "20" }
 }`
How many items are read by the DynamoDB query operation?

Answer options:

A.1
B.2
C.3
D.4

Answer: C
The query operation is used to search items based on primary key values.The name of the partition key attribute and a single value for that attribute must be provided with the query. The query returns all items with that partition key value. A filter expression parameter can be used to narrow down the results based on some required criteria. A filter expression is applied AFTER a query operation competes, but BEFORE the results are returned to the client. Therefore, a query operation consumes the same amount of read capacity, regardless of whether a filter expression is present.This means that all items with the primary key of “Albert Einstein” are returned for the query operation in this scenario.Thus, the correct answer is 3.
Reference:
https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Query.html