Correct answer:
C) esa mesa es amarilla
Esa is the feminine singular form of the demonstrative adjective ese. The demonstrative pronouns, such as este, ese and aquel can act as demonstrative adjectives when placed before a noun. So these adjectives demonstrate a quality about the noun they modify. Here that quality is the location in respect to the speaker or the listener. Ese indicates something more distant, that is, nouns that are further from the speaker but they can be close to the listener. We use esa because the noun in this sentence, which is mesa, is singular and feminine and recall that adjectives must agree with the nouns they modify in both gender and number. Finally:
Esa mesa es amarilla (that table is yellow)