Which of the following is$/$are correct for Google's Bigtable solution?

Question $14$Select one or more:

a$.$

Tablets are the basic units of access control.

b$.$

Column families within a $($big$)$ table can be dynamically created $($i$.$e$.,$ no need to predefine a column family before data is stored under any column key in that family$).$

c$.$

Columns are the basic units of distribution and load balancing.

d$.$

The choice of row$-$keys affects partitioning of rows into tablets.

e$.$

In a $($big$)$table$,$ columns are grouped into column families, and columns within a column family are pre$-$defined by the schema of the $($big$)$table$.$