Answer give by ICAI is exactly as per SA 620 they have picked content directly from some foreign book etc
but its simple and short answer student explains from SA 620 he should get marks, as many points are common also
Specific Procedures

1st Observing (selective work) the auditor’s expert’s work (When expert is doing his work)
2nd Reviewing the auditor’s expert’s reports & working papers (after he has finished his work)

while observing and reviewing reports & working papers

1. Enquiries of the auditor’s expert  (Clearing doubts)
2. Examining the published data, such as statistical reports from reputed source (matching with external data)
3. Confirming the relevant matters with third parties
4. Discussions with another expert with relevant expertise when, for example, the findings or the conclusion of the auditor’s expert are not consistent with other audit evidence.

Procedures while finishing work

1. Performing detailed analytical procedure to see whether principles of materiality aspects considered
2. Re performing calculations
3. Discussing the expert’s report with the management