To answer this question, the user needs to know the types of clusters in IBM's Information Management System (IMS) and which clusters support alternate indexes.

An alternate index is an index created on one or more non-key fields of a base segment in IMS. It provides an alternate way of accessing the base segment data.

Now, let's go through each option and explain which cluster types support alternate indexes:

A. KSDS and RRDS - This option is incorrect. Although Key Sequenced Data Set (KSDS) supports alternate indexes, Relative Record Data Set (RRDS) does not.

B. KSDS and ESDS - This option is correct. KSDS and Entry Sequenced Data Set (ESDS) both support alternate indexes.

C. KSDS and LDS - This option is incorrect. Although KSDS supports alternate indexes, Linear Data Set (LDS) does not.

D. KSDS only - This option is incorrect. Although KSDS supports alternate indexes, ESDS also supports it.

Therefore, the correct answer is:

The Answer is: B. KSDS and ESDS.