The major drawback of RAD model is

If in the words, all the letters are arranged in English alphabetical order within the word, how many words will begin with a vowel?

Select the letter-cluster from among the given options that can replace the question mark (?) in the following series.

WUW, TSV, QQU, NOT, ?

Select the letter-cluster from among the given options that can replace the question mark (?) in the following series.

TSF, RPJ, PMN, NJR, ?

Four letter-clusters have been given, out of which three are alike in some manner and one is different. Select the letter-cluster that is different.

Select the letter-cluster that can replace the question mark (?) in the following series. CXB, HUI, MRP, ROW, ?

Select the set of letters that when sequentially placed in the blanks of the given letter series will complete the series.

_SWWS_WWWS_SWWWW_SSS

Which among the following word cannot be formed using the letters of the given word only once?

CONTRADICTION

Directions: From the given alternative words, select the word which can be formed using the letters of the given word. 

PORTFOLIO 

Select the combination of letters that when sequentially placed in the blanks will create a repetitive pattern.

a_be_a_beda_ccd_bed_