E9H04

What is the purpose of placing an electrostatic shield around a small-loop direction-finding antenna?

1. AIt adds capacitive loading, increasing the bandwidth of the antenna
2. BIt eliminates unbalanced capacitive coupling to the antenna's surroundings, improving the depth of its nulls
3. CIt eliminates tracking errors caused by strong out-of-band signals
4. DIt increases signal strength by providing a better match to the feed line

Pick an answer to check it.