A sender is employing public key Cryptography to send a secret message to a receiver. Which one of the following statement is true?

What is the result of evaluating the following two expressions using three $$-$$ digit floating point arithmetic with rounding?
$$\eqalign{ & \left( {113. + - 111.} \right) + 7.51 \cr & 113. + \left( { - 111. + 7.51} \right) \cr} $$

$$A$$ $$4$$-bit carry look ahead adder, which adds two $$4$$-bit numbers, is designed using $$AND,$$ $$OR,$$ $$NOT,$$ $$NAND,$$ $$NOR$$ gates only. Assuming that all the inputs are available in both complemented and uncomplemented forms and the delay of each gate is one time unit, what is the overall propagation delay of the adder? Assume that the carry network has been implemented using two-level $$AND$$-$$OR$$ logic.

Consider a small two-way set-associative cache memory, consisting of four blocks. For choosing the block to be replaced, uses the least recently used $$(LRU)$$ scheme. The number of cache misses for the following sequence of blocks addresses is $$8,12,0,12,8$$