The correct answer is D. both B and C.
Serial correlation, also known as autocorrelation, is a statistical phenomenon in which the value of a variable at a given time is correlated with its value at previous or future times. This means that the residuals, which are the differences between the actual values and the predicted values, are not independent of each other. This can cause problems with statistical inference, such as making the standard errors of the estimates too small.
Parallel correlation is a type of correlation in which the residuals are correlated with each other, but the correlation is not dependent on the time order of the data. This can also cause problems with statistical inference, but it is not as serious as serial correlation.
In conclusion, the problem which arises because of presence of systematic pattern in residual value sequence is considered as both serial correlation and parallel correlation.