The momentum equation is $d\frac{u}{d}t=-$del$\frac{p}{d}$elx$+$delT$\frac{}{d}$elx$+$delTy$\frac{x}{d}$ely$+$delTz$\frac{x}{d}$elz$\frac{+}{}fx.$ Which of these statements about sign convention can be inferred from this equation?

Pressure force is unsigned

Tensile force is taken as negative

Pressure force is taken as positive

Pressure force is taken as negative