Answer:
3400, Rise, C
Explanation:
1. Since there are just 3 firms and two already has a sum total of 70% (40+30), the third firm will have a market share of 30%
HHI=
HHI= 1600+900+900
HHI= 3400
2. Abe's Bikes with 30% leaves the market, if the two firms were to share Abe's market share equally (15+15), it will leave Firm A with 55% (40+15) and Firm B with (30+15) 45%
Therefore,
HHI= 
HHI=3025+2025
HHI= 5050
A rise in HHI
3. C
An index of 10,000 corresponds to a monopoly firm with 100% market share.
Answer: I. must establish an SEC-registered U.S. subsidiary.
III. can effect its business through another registered U.S. broker-dealer.
Explanation:
If a foreign broker-dealer that does not have U.S. based operations wishes to solicit customers in the United States, the broker-dealer must establish an SEC-registered U.S. subsidiary and can also effect its business through another registered U.S. broker-dealer.