Which three methods could transparently help to achieve this result?

A warehouse fact table in your Oracle 12c Database is range-partitioned by month and accessed
frequently with queries that span multiple partitions
The table has a local prefixed, range partitioned index.
Some of these queries access very few rows in some partitions and all the rows in other partitions,
but these queries still perform a full scan for all accessed partitions.
This commonly occurs when the range of dates begins at the end of a month or ends close to the
start of a month.
You want an execution plan to be generated that uses indexed access when only a few rows are
accessed from a segment, while still allowing full scans for segments where many rows are
returned.
Which three methods could transparently help to achieve this result?

A.
Using a partial local Index on the warehouse fact table month column with indexing disabled to
the table partitions that return most of their rows to the queries.

B.
Using a partial local Index on the warehouse fact table month column with indexing disabled for
the table partitions that return a few rows to the queries.

C.
Using a partitioned view that does a UNION ALL query on the partitions of the warehouse fact
table, which retains the existing local partitioned column.

D.
Converting the partitioned table to a partitioned view that does a UNION ALL query on the
monthly tables, which retains the existing local partitioned column.

E.
Using a partial global index on the warehouse fact table month column with indexing disabling
for the table partitions that return most of their rows to the queries.

F.
Using a partial global index on the warehouse fact table month column with indexing disabled
for the table partitions that return a few rows to the queries.

Explanation:

Note:
* Oracle 12c now provides the ability to index a subset of partitions and to exclude the others.

Local and global indexes can now be created on a subset of the partitions of a table. Partial Global
indexes provide more flexibility in index creation for partitioned tables. For example, index
segments can be omitted for the most recent partitions to ensure maximum data ingest rates
without impacting the overall data model and access for the partitioned object.
Partial Global Indexes save space and improve performance during loads and queries. This
feature supports global indexes that include or index a certain subset of table partitions or
subpartitions, and exclude the others. This operation is supported using a default table indexing
property. When a table is created or altered, a default indexing property can be specified for the
table or its partitions.