Which of the following pairs is not correctly matched?

PYQ UPPSC LT Grade (Assistant Teacher) 2025

1. A.

   The projection of the vector î + ĵ + k̂ in the ĵ direction : 1

2. B.

   If |a⃗ + b⃗| = |a⃗ − b⃗|, then angle between a⃗ and b⃗ is : π/4

3. C.

   The non-zero vectors a⃗, b⃗ and c⃗ are related by a⃗ = 8b⃗, c⃗ = −7b⃗, then angle between a⃗ and c⃗ is : π

4. D.

   If |a⃗| = 3, |b⃗| = 4 and |a⃗ + b⃗| = 1, then |a⃗ − b⃗| is : 7

Attempted by 6 students.