A student wrote two context-free grammars G1 and G2 for generating a single $$C$$-like array declaration. The dimension of the array is at least one. For example, $$${\mathop{\rm int}} \,\,\,\,\,\,\,a[10]\,\,[3];$$$

The grammars use D as the start symbol, and use six terminal symbols int ; id [ ] num.

Grammar G1	Grammar G2
D → intL;	D → intL;
L → id[E	L → idE
E → num	E → E[num]
E → num][E	E → [num]

Which of the grammars correctly generate the declaration mentioned above?

In an Ethernet local area network, which one of the following statements is TRUE?

For the IEEE 802.11 MAC protocol for wireless communication, which of the following statements is/are TRUE?

I. At least three non-overlapping channels are available for transmissions.
II. The RTS-CTS mechanism is used for collision detection.
III. Unicast frames are ACKed.

A network has a data transmission bandwidth of 20 × 10⁶ bits per second. It uses CSMA/CD in the MAC layer. The maximum signal propagation time from one node to another node is 40 microseconds. The minimum size of a frame in the network is __________ bytes.