The quark composition of the proton and neutron are, respectively, uud and udd, where u is an up quark (charge +23e) and d is a down quark (charge −13e). There are also anti-up u¯ (charge −23e) and anti-down d¯ (charge +13) quarks. The combination of a quark and an antiquark is called a meson. The mesons known as pions have the composition π+=ud¯ and π−=u¯d. Suppose a proton collides with an antineutron. During such collisions, the various quarks and antiquarks annihilate whenever possible. When the remaining quarks combine to form a single particle, it is a:.A) ProtonB) NeutronC) π+D) π−