You are provided with the following information on prices in some commodity futures.

Date	Futures Price	Spot Price
1/20	24.2	21.05
1/21	23.88	22.09
1/25	24.5	24.01
2/5	23.21	21.92
2/7	24	23.16
2/10	24.15	24.04
2/12	24.25	24.63
2/15	25.64	25.61
2/18	25.18	26.19
2/19	24.57	26.28
2/23	23.91	24.56
3/1	24.83	25.72
3/3	25.17	25.36
3/6	25.33	27.01
3/8	24.21	26.81
3/12	24.92	26.24
3/21	25.35	24.03
3/22	25.84	25.19
4/5	25.52	25.10
4/9	24.78	23.23
4/16	25.38	23.45
4/20	24.83	23.05
4/22	23.25	21.03
4/28	24.12	20.59
5/1	24.46	20.18
5/7	24.51	20.02
5/10	24.6	20.48
5/12	24.77	21.16
5/14	24.09	20.87
5/15	24.03	20.15
5/21	24.15	26.14
5/29	23.88	26.19
6/2	23.95	26.89
6/7	24.02	26.71
6/11	24.27	25.67
6/13	24.25	23.03
6/17	24.81	23.94
6/18	24.41	20.22
6/24	24.43	20.01
6/25	23.57	19.81
6/27	23.71	20.66
6/29	23.55	22.35

Suppose that you have a long position on this futures contract. The maturity month of the contract is on July 2021. Let the initial spot price be $21.05 per unit when you started the futures position, and each futures contact has 1000 units. Suppose the initial margin for the futures position is 30% of the initial contract value, the maintenance margin is $6,700. Answer the following questions;

a) How much have you deposited in all together in maintaining your futures position until 06/29? What is the balance on your futures account? Show this in details on Excel spreadsheet.

b) Suppose the spot prices are shown as above, does this show an arbitrage opportunity to you if the risk-free rate is 2%? Are you making money if you are on the short side when approaching the maturity date?