Number of record in data file $=2000$

Block size $105B$

Blocking factor$=\left \lfloor \frac{105}{10} \right \rfloor=10$

Number of blocks in 1st level index$=\left \lceil \frac{2000}{10} \right \rceil=200$

Number of blocks in 2nd level index$=\left \lceil \frac{200}{10} \right \rceil=20$

Number of blocks in 3rd level index$=\left \lceil \frac{20}{10} \right \rceil=2$

Number of blocks in 4th level index$=\left \lceil \frac{2}{10} \right \rceil=1$

So, total block access=index block access+data block access=$=4+1=5$

Hope ur doubt clear now