Choice-A is the correct one. It doesn't say it, but it means he'll see the ball reach the catcher's mitt first BEFORE HE HEARS IT slap the mitt.
40% of the Earth's surface is covered by continental crust.
<span> A wavelenght is the distance between successive crests of a wave, especially points in a sound wave or electromagnetic wave.
</span>The diode laser operates at a wavelength<span> of 410 nm.</span>
D, which is around the speed of light
The fundamental closeness is they have a similar like charges repulse each other, distinctive charges pull in each other. While their distinction is that attractive "charges" can't be isolated. At any rate, so far it has not been accomplished. I trust this makes a difference.