Force direction depends on field type and charge sign Steps:

• Electric field direction is defined by force on positive test charge.
• Force on charge is F = qE; if q > 0, force parallels E; if q < 0, force opposes E.
• Gravitational field g points in direction of force on any mass (m > 0 always), so F = mg aligns with g.
• Observed opposite force-field direction matches electric field with negative charge only.

Why B is correct:

• Negative charge in electric field experiences force opposite to E, as q < 0 reverses F = qE direction.

Why the others are wrong:

• A: Positive charge in electric field has force in same direction as E.
• C: No negative gravitational "charge" exists; force always follows field.
• D: Gravitational force always aligns with field for positive mass.

Final answer: B