For first question answers are B,C,E
We have three options to transfer data to SAP
1 SLT
2 DXC
3 Data Services using BODS
SLD is a different concept while Open hub is used to send data from SAP BW to external sources
Second - A as i don't think there is SAP_DATA_ADMIN privilege, if its there answer would be B
Well the best way to apply restriction is to use Analytic Privileges
Third - A
the answer should be A but it also should add WITH GRANT OPTION
GRANT SELECT on SCHEMA "XYZ" to _SYS_REPO WITH GRANT OPTION