= Solution
\b[Dependence on Grassmann variables alone does not specify a superfield transformation law.] A <superfield> is a function on <superspace>, with components transforming under the induced <supertranslation> and <Lorentz transformation> action. Any suitable superfunction can be an unconstrained <superfield> once equipped with that action; a fixed element of a <Grassmann algebra> with independently assigned components need not be covariant. A <chiral superfield>, for example,
$$
\Phi(y,\theta)=A(y)+\sqrt2\theta\psi(y)+\theta^2F(y),\qquad y^\mu=x^\mu+i\theta\sigma^\mu\bar\theta,
$$
also obeys $\bar D_{\dot\alpha}\Phi=0$. Keeping only a nonconstant $A(x)$ and forbidding the other components is not a closed <supermultiplet>: applying a <supercharge> generates Grassmann-dependent derivative terms. A real unconstrained <superfield> can instead describe a <vector superfield>.
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