担当の方はどなたですか。

being in charge (of an area of responsibility); being responsible (for a work role, etc.)

indicates possessive; nominalizes verbs and adjectives; substitutes for "ga" in subordinate phrases; (at sentence-end, falling tone) indicates a confident conclusion; (at sentence-end) indicates emotional emphasis; (at sentence-end, rising tone) indicates question

direction; way; person; lady; gentleman; method of; manner of; way of; care of ..; person in charge of ..; side (e.g. "on my mother's side")

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

who?

be; is

indicates a question (sometimes rhetorical); or; whether or not; some- (e.g. something, someone); indicates doubt, uncertainty, etc.; emphatic prefix; suffix forming adjectives or adverbs; in that way