Which of the following alternative will fill the blanks? m_u_mg_p_gu_

Correct — A.
Rule: the unit mgup repeats three times.

Split into blocks of four: m_u_ | mg_p | _gu_
Block 1: m g u p
Block 2: m g u p
Block 3: m g u p

Blanks in order: g, p, u, m, p → option (a).

Why the others are wrong

• (b)
  g,p,u,p,m — Right for the first three blanks, but it swaps the last two: block 3 would read pgum, not mgup.
• (c)
  p,u,u,p,m — Block 1 would read mpuu and block 3 pgum. Neither matches the middle block, mgup, so nothing repeats.
• (d)
  p,p,u,m,g — Block 1 becomes mpup and block 3 mgug. Neither matches the middle block, mgup.

In a blank-filling series, a short unit of letters repeats and some places are blanked out. First find the unit's length from the letters you can see.

Here m stands at places 1 and 5, and g at places 6 and 10: both four apart. So the 12 places are three blocks of four. The middle block, mg_p, is nearly complete and gives the unit mgup. Copy it into the other two blocks.

Key facts

• m_u_mg_p_gu_ has 12 places: three blocks of four.
• Filled, the line reads mgup mgup mgup.
• Visible letters four places apart (m at 1 and 5, g at 6 and 10) fix the unit length.

Common traps

• Checking only the first block, which options (a) and (b) both fill correctly
• Guessing the unit from alphabetical order instead of from the printed letters

No directly related past PYQ was found.