yes,you can only create one clustered index on a table.

Clustered index based on Primary Key. So if we create a PK,
automatically Clustered Index will be created. So only one
CI available for a table.

Clustered Index creation does not depend upon primary key , 
it can be created on any column, but the write answer is 
whenever we create clustered index on a table it physically
sorts the column values, so another clustered index is not 
possible.

we can create ony ONE clustered index per table .. for Non-
clusrtered index we can create 249 ...

A clustered index sorts and stores the data rows in the
table based on the index key values. Therefore only one
clustered index can be created on each table because the
data rows themselves can only be sorted in one order.

Because cluster index sort data in table based on key value that is you primary key value and primary key values are unique in table therefore cluster index only one on table.