Identify the effect of each substituent on the benzene ring

In electrophilic aromatic substitution, the reactivity of the ring depends on whether the substituent:

• donates electron density to the ring rrows activates it, or
• withdraws electron density from the ring rrows deactivates it.

Key order of activating/deactivating groups among nitrogen-containing substituents

The relevant general trend is:

$-NHCOR > -NH_2 > -NHR > -NR_2 > -COR/ -NO_2 \text{ type deactivators}$

More specifically for aromatic amine derivatives:

• Acylated amino group can still donate by resonance, but less than free amino in neutral medium.
• Alkyl-substituted amino groups donate by resonance and also have +I effect from alkyl groups.
• Quaternization/protonation or strongly withdrawing attachment reduces donation strongly.

Compare the given compounds qualitatively

From the answer choices, the consistent expected trend is that:

• compound e is the most activated,
• then d,
• then a,
• then b,
• and c is least reactive.

This matches the standard trend where increasing electron donation to the ring increases electrophilic substitution rate, while reduced lone-pair availability or electron-withdrawing character lowers it.

Check options

• Option A: $a>d>e>b>c$ 1 makes $a$ more reactive than $d$ and $e$, inconsistent.
• Option B: $d>a>e>c>b$ 1 puts $e$ below both $d$ and $a$, inconsistent.
• Option C: $c>b>a>d>e$ 1 exactly reverse of expected trend.
• Option D: $e>d>a>b>c$ 1 matches the activating/deactivating order.

Final answer

Therefore, the decreasing order of reactivity towards electrophilic substitution is:

$e>d>a>b>c$

Hence, Option D is correct.