In a $\mathrm{B}^{+}$- tree where each node can hold at most four key values, a root to leaf path consists of the following nodes:

$$A=(49,77,83,-), B=(7,19,33,44), C=\left(20^*, 22^*, 25^*, 26^*\right)$$

The *-marked keys signify that these are data entries in a leaf.

Assume that a pointer between keys $k_1$ and $k_2$ points to a subtree containing keys in [ $k_1, k_2$ ], and that when a leaf is created, the smallest key in it is copied up into A record with key value 23 is inserted into the $\mathrm{B}^{+}$- tree.

The smallest key value in the parent of the leaf that contains $25^*$ is _________ . (Answer in integer)

Consider the following logic circuit diagram.

Which is/are the CORRECT option(s) for the output function?

The following two signed 2's complement numbers (multiplicand M and multiplier Q ) are being multiplied using Booth's algorithm :

M : 1100110111101101 and Q : 1010010010101010

The total number of addition and subtraction operations to be performed is ________ (Answer in integer)

In a 4-bit ripple counter, if the period of the waveform at the last flip-flop is 64 microseconds, then the frequency of the ripple counter in kHz is _________. (Answer in integer)