Indicate whether the following conditions can exist for a chemical reaction: (a) r H < 0

Indicate whether the following conditions can exist for a chemical reaction:

(a) Δ_rH < 0 < E_a; 

(b) 0 < Δ_rH < E_a; 

(c) 0 < E_a < Δ_rH; 

(d) 0 = Δ_rH < E_a; 

(e) E_a < Δ_rH <0. 

Where the conditions can exist, describe the reaction profile.