The following are four different relations about displacement, velocity, and acceleration for the motion of a particle in general. Choose the incorrect statement(s):

(a) v_av = 1/2 [v(t₁) + v(t₂)]

(b) v_av = r(t₂)-r(t₁)/t₂-t₁

(c) r = 1/2 [v(t₂)-v(t₁)](t₂-t₁)

(d) a_av = v(t₂)-v(t₁)/t₂-t₁

1. (a), d)

2. (a), c)

3. (b), c)

4. (a), b)