Which statement is true of a wave that’s propagating along the pavement and girders of a suspension bridge? a. the wave is mechanical, with particles vibrating in a direction that is parallel to that of the wave, forming compressions and rarefactions. b. the wave is electromagnetic, with particles vibrating in a direction that is parallel to that of the wave, forming compressions and rarefactions. c. the wave is mechanical, with particles vibrating in a direction that is perpendicular to that of the wave, forming crests and troughs. d. the wave is electromagnetic, with particles vibrating in a direction that is perpendicular to that of the wave, forming crests and troughs. e. the wave is mechanical, with particles vibrating in a direction that is perpendicular to that of the wave, forming compressions and rarefactions.