If cell is empty copy line x times and fill the blanks with predetermined text

Hello - I am fairly new to VBA so appreciate any help or guidance. Thank you

I have 4 columns of data where the random blank in col C signify condensed lines. The creator wanted to reduce the # of lines so saw the pattern repeated in this cell and ignored it and removed the duplicates and said the blank represents D1,D2,D3,D5,D7,D8. I need the duplicates re-instated and these values added back in.

and I need quick way to transform the data and expand the condensed form that where finds an empty cell in column C - duplicates/copies that row 5 times making a total of 6 lines and then adds/fill each blank cell with the 6 unique text value (i.e D1,D2 etc.) and then repeat until all blanks have been expanded back out from approx. 2000 lines of data to 8000.

COL INT LEX PV
345000 A 3654898
258000 C D2 6987450
258000 C D5 6987450
258000 C D7 6987450
103698 D 8521030