Accommodation is the eye’s ability to add focusing power for near vision, and that ability is maximal in young children because the lens is highly elastic. Its magnitude is estimated using Hofstetter’s average-amplitude rule:
\[ A_{\text{avg}} = 18.5 - 0.30 \times \text{age (years)} \]
Substituting age $= 7$:
$A = 18.5 - 0.30(7) = 18.5 - 2.1 = 16.4\ \text{D}$
This calculation lands the value in the mid-teens of dioptres, and the matching option offered is +14 D. The other choices correspond to older ages - about +10 D in adolescence and +5 D near the late thirties - reflecting the steady decline that culminates in presbyopia. So for a 7-year-old, the expected accommodative power is approximately +14 D.
\[\boxed{+14\ \text{D}}\]