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?

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.

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.