Concept:
Days repeat every 7 days, so we use modulo:
\[
{Day after } n { days} = n \bmod 7
\]
Step 1: Find remainder.
\[
200 \div 7 = 28 { remainder } 4
\]
Step 2: Count 4 days from Sunday.
\[
{Sunday} \rightarrow {Monday (1)} \rightarrow {Tuesday (2)} \rightarrow {Wednesday (3)} \rightarrow {Thursday (4)}
\]
Hence, the day will be Thursday.