Im not 100% but i think the answer is d. :}
I think the questions that must be ask are:
a.What does “encryption” mean?
d.What are “key distribution problems”?
All the text is based on the concept "encryption" so it is very important to know what it means in order to undestand the rest of the information. If not, you will be missing important facts. In addition, there are a lot of words used that are derived from this one, so you won't be able to undestand them.
Another important concept that gives a lot of information just by knowing it's meaning is "key distribution problems", they could be two or a thousand, it is important to know what they are and what they do.
The other question that seems important is the one of the "public key cryphtography" but this one can be inferred by the context.
Answer:
Dear Father,
In his letter, Nadeem has informed me that mother is not feeling well. He has given me a hint about her poor health. I am much disturbed to know all of this. I am sure, you will be taking proper care of her. She is the patient of high blood pressure and sugar.
It is better to get her checked by a specialist. Further, kindly arrange a whole time nurse for her, who can take care of her on regular basis.
Please keep in touch With me in this regard.
Yours affectionately,
Joe.
Explanation:
C - Saturday
All days of the week must be capitalised.
