The most appropriate answer is B !!
Covalent bond is formed by sharing of electrons !!
Because it is a covalent bond meaning that they share the electrons to achieve full valence.
A.chloroplast
Chloroplasts performs photosynthesis during daylight hours
Number of photons can be calculated by dividing the needed energy by the energy per photon.
The minimum energy needed is given as 2 x 10^-17 joules
Energy per photon = hc / lambda where h is planck's constant, c is the speed of light and lambda is the wavelength
Energy per photon = (<span>6.626 x 10^-34 x 3 x 10^8) / (475 x 10^-9)
= 4.18 x 10^-19 J
number of photons = (2 x 10^-17) / (4.18 x 10^-19)
= 47.79 photons which is approximately 48 photons</span>