excel column c ans ? how ?

PROJECT NAME ANS
TASK_001 mukesh mukesh solanki
TASK_001 solanki
TASK_002 RAVI RAVI KISHAN SHARMA
TASK_002 KISHAN
TASK_002 SHARMA
TASK_003 MS MS
TASK_004 SJ SJ
TASK_005 D DKC
TASK_005 K
TASK_005 C
PROJECT NAME ANS
TASK_001 mukesh mukesh solanki
TASK_001 solanki
TASK_002 RAVI RAVI KISHAN SHARMA
TASK_002 KISHAN
TASK_002 SHARMA
TASK_003 MS MS
TASK_004 SJ SJ
TASK_005 D DKC
TASK_005 K
TASK_005 C
How did the answer of C column come, by applying which formula, the names of B column got added and came in C column?
How did the answer of C column come, by applying which formula, if there is only one type of project, then all the names of its next column i.e. B column should come in C column.