The table given below gives the annual details of loans from rural banks and agricultural loans over the years 1970 to 1983. Using this data answer the questions that follow
| 2*Year | Loan from Rural Banks | No. ($'000$) | ||
|---|---|---|---|---|
| Number of rural banks | Average number of loans | Average size (in Rs.) | ||
| $1970$ | $90$ | $28$ | $109$ | $18.3$ |
| $1971$ | $115$ | $39$ | $133$ | $20.4$ |
| $1972$ | $130$ | $52$ | $178$ | $25.1$ |
| $1974$ | $260$ | $98$ | $243$ | $41.2$ |
| $1975$ | $318$ | $121$ | $283$ | $51.4$ |
| $1980$ | $605$ | $288$ | $567$ | $135.7$ |
| $1981$ | $665$ | $312$ | $622$ | $152.8$ |
| $1983$ | $840$ | $380$ | $711$ | $211.6$ |




| A | B | C | D | Average |
|---|---|---|---|---|
| 3 | 4 | 4 | ? | 4 |
| 3 | ? | 5 | ? | 4 |
| ? | 3 | 3 | ? | 4 |
| ? | ? | ? | ? | 4.25 |
| 4 | 4 | 4 | 4.25 |
For any natural number $k$, let $a_k = 3^k$. The smallest natural number $m$ for which \[ (a_1)^1 \times (a_2)^2 \times \dots \times (a_{20})^{20} \;<\; a_{21} \times a_{22} \times \dots \times a_{20+m} \] is: