To answer this question, we need to understand what the term "BUFSIZE" refers to and what its default value is.
BUFSIZE typically refers to the size of a buffer, which is a temporary storage area used to hold data while it is being transferred from one location to another. The default BUFSIZE value is the default size allocated for this buffer.
The correct answer is D) 4096. This option is correct because the default BUFSIZE is commonly set to 4096 bytes.